' Getting started with AT91SAM7S devices

' Port to HBBR Basic
' Copyright (c) 20072-008, Hobby-Robotics, LLC 

' Copyright notice in the original C based code 
'/* ----------------------------------------------------------------------------
' *         ATMEL Microcontroller Software Support  -  ROUSSET  -
' * ----------------------------------------------------------------------------
' * Copyright (c) 2006, Atmel Corporation
' *
' * All rights reserved.
' *
' * Redistribution and use in source and binary forms, with or without
' * modification, are permitted provided that the following conditions are met:
' *
' * - Redistributions of source code must retain the above copyright notice,
' * this list of conditions and the disclaiimer below.
' *
' * - Redistributions in binary form must reproduce the above copyright notice,
' * this list of conditions and the disclaimer below in the documentation and/or
' * other materials provided with the distribution.
' *
' * Atmel's name may not be used to endorse or promote products derived from
' * this software without specific prior written permission.
' *
' * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
' * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
' * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
' * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
' * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
' * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
' * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
' * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
' * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
' * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
' * ----------------------------------------------------------------------------
' */

' Global variables
Const LED_A             As Integer = &B0001                     ' PA0     AT91B_LED1
Const LED_B             As Integer = &B0010                     ' PA1     AT91B_LED2
Const BUTTON_A          As Integer = &B010000000000000000000    ' PA19     AT91B_BP1
Const BUTTON_B          As Integer = &B100000000000000000000    ' PA20     AT91B_BP2
Const ID_PIO_BP         As Integer = &H2                        ' AT91D_ID_PIO_SW = AT91C_ID_PIOA

Const DEBOUNCE_TIME     As Integer = 500

' The following global variables, control the LED blinking 
Dim led_a_active As Boolean = True
Dim led_b_active As Boolean = True
Dim jiffies As Integer = 0

'-----------------------------------------------------------------------------
' * Function Name       : pabt_handler
' * Object              : Prefetch Abort Handler
' *---------------------------------------------------------------------------
'
' Currently custom Prefetch Abort Handler can not be installed by the user
'
Irq pabt_handler()
	Call dbgu_print_ascii("-F- Prefetch abort at ")
	Call dbgu_print_hex8(AT91C_MC_AASR)
	Call dbgu_print_ascii("\n\r")
End Irq

'-----------------------------------------------------------------------------
' * Function Name       : dabt_handler
' * Object              : Data Abort Handler
' *---------------------------------------------------------------------------
'
' Currently custom Data Abort Handler can not be installed by the user
'
Irq dabt_handler()
	Call dbgu_print_ascii("-F- Data abort at ")
	Call dbgu_print_hex8(AT91C_MC_AASR)
	Call dbgu_print_ascii("\n\r")
End Irq

'-----------------------------------------------------------------------------
' * Function Name       : pitc_handler
' * Object              : Handler for PITC interrupt
' *---------------------------------------------------------------------------
Irq pitc_handler()
    Dim pivr As Integer = 0
    Dim pisr As Integer = 0

    ' Read the PISR 
    pisr = AT91C_PITC_PISR And AT91C_PITC_PITS
    If (pisr <> 0)  Then 
        ' Read the PIVR. It acknowledges the IT 
        pivr = AT91C_PITC_PIVR

        ' Add to jiffies PICNT: the number of occurrences of periodic intervals  
        ' since the last read of PIT_PIVR 
        jiffies = jiffies + (pivr >> 20)
    End If 

End Irq


'-----------------------------------------------------------------------------
' * Function Name       : configure_pit
' * Object              : Configure priodic interval timer
' *---------------------------------------------------------------------------
Sub configure_pit()

    Dim pimr As Integer = 0

    ' Configure a resolution of 1 ms 
    AT91C_PITC_PIMR = __conf_MCK  \ (16 * 1000) - 1 ' AT91B_MASTER_CLOCK
    
    ' Enable interrupts 
    ' Disable the interrupt on the interrupt controller 
    AT91C_AIC_IDCR = (1 << AT91C_ID_SYS)

    ' Save the interrupt handler routine pointer and the interrupt priority 
    ' AT91C_AIC_SVR[AT91C_ID_SYS] = pitc_handler
    AT91C_AIC_SVR1 = CInt(AddressOf pitc_handler)                                       ' AT91C_ID_SYS = &H1
 
    ' Store the Source Mode Register 
    ' AT91C_AIC_SMR[AT91C_ID_SYS] = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST
    AT91C_AIC_SMR1 = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST   ' AT91C_ID_SYS = &H1

    ' Clear the interrupt on the interrupt controller 
    AT91C_AIC_ICCR = (1 << AT91C_ID_SYS)

    ' Enable the interrupt on the interrupt controller 
    AT91C_AIC_IECR = (1 << AT91C_ID_SYS)

    ' Enable the interrupt on the pit 
    pimr = AT91C_PITC_PIMR
    AT91C_PITC_PIMR = pimr Or AT91C_PITC_PITIEN

    ' Enable the pit 
    pimr = AT91C_PITC_PIMR
    AT91C_PITC_PIMR = pimr Or AT91C_PITC_PITEN

End Sub

'-----------------------------------------------------------------------------
' * Function Name       : button_handler
' * Object              : Button Interrupt Service Routine (PIO A)
' *---------------------------------------------------------------------------
Irq button_handler()

    ' Read the Interrupt Status register (It acknowledge the IT)  
    Dim pio_isr As Integer    ' = AT91C_PIOA_ISR
    Dim pio_pdsr As Integer   ' = AT91C_PIOA_PDSR
    Dim button_a_jiffies As Integer = 0
    Dim button_b_jiffies As Integer = 0

    pio_isr = AT91C_PIOA_ISR
    pio_pdsr = AT91C_PIOA_PDSR

    ' If the BUTTON_A has been pushed or released 
    If (CBool(pio_isr And BUTTON_A)) Then 
        ' Enable/disable the LED A blinking when BUTTON_A is released 
        If (CBool(pio_pdsr And BUTTON_A))Then 
              If (jiffies - button_a_jiffies > DEBOUNCE_TIME) Then
                button_a_jiffies = jiffies
                led_a_active = Not led_a_active
              End If
        End If
    ' If the BUTTON_B has been pushed or released 
    ElseIf (CBool(pio_isr And BUTTON_B)) Then
        ' Enable/disable the LED B blinking when BUTTON_B is pushed 
        If (Not CBool(pio_pdsr And BUTTON_B)) Then
              If (jiffies - button_b_jiffies > DEBOUNCE_TIME) Then
                    button_b_jiffies = jiffies
                    If (led_b_active) Then
                          ' Disable the clock 
                          AT91C_TC0_CCR = AT91C_TC_CLKDIS
                    Else 
                          ' Clock is started 
                          AT91C_TC0_CCR = AT91C_TC_CLKEN
                          ' Counter is reset and the clock is started 
                          AT91C_TC0_CCR = AT91C_TC_SWTRG
                    End If
                    led_b_active = Not led_b_active
              End If
        End If
    ' The Else should not be executed since no other PIO are enabled  
    Else 
    End If
End Irq


'-----------------------------------------------------------------------------
' * Function Name       : configure_buttons
' * Object              : Configure pios to capture buttons state
' *---------------------------------------------------------------------------
Sub configure_buttons()

    ' Enable the periph clock for the PIO controller 
    ' This is mandatory when PIO are configured as input 
    AT91C_PMC_PCER = (1 << ID_PIO_BP)

    ' Set the PIO line in input 
    AT91C_PIOA_ODR = (BUTTON_A Or BUTTON_B)

    ' Set the PIO controller in PIO mode instead of peripheral mode 
    AT91C_PIOA_PER = (BUTTON_A Or BUTTON_B)

    ' Disable the interrupt on the interrupt controller 
    AT91C_AIC_IDCR = (1 << ID_PIO_BP)

    ' Save the interrupt handler routine pointer and the interrupt priority 
    ' TBI AT91C_AIC_SVR[ID_PIO_BP] = button_handler
    AT91C_AIC_SVR2 = CInt(AddressOf button_handler) ' ID_PIO_BP AT91C_ID_PIOA = &H2

    ' Store the Source Mode Register 
    ' AT91C_AIC_SMR[ID_PIO_BP] = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST
    AT91C_AIC_SMR2 = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST ' ID_PIO_BP AT91C_ID_PIOA = &H2

    ' Clear the interrupt on the interrupt controller 
    AT91C_AIC_ICCR = (1 << ID_PIO_BP)

    ' Enable button interrupts generation through the PIO controller 
    AT91C_PIOA_IER = (BUTTON_A Or BUTTON_B)

    ' Enable PIO interrupt in the interrupt controller 
    AT91C_AIC_IECR = (1 << ID_PIO_BP)

End Sub


'-----------------------------------------------------------------------------
' * Function Name       : configure_leds
' * Object              : Configure pios to control led states
' *---------------------------------------------------------------------------
Sub configure_leds()

  ' Configure the pin in output 
  AT91C_PIOA_OER = (LED_A Or LED_B)
  ' Set the PIO controller in PIO mode instead of peripheral mode 
  AT91C_PIOA_PER = (LED_A Or LED_B)
  ' Disable pull-up 
  AT91C_PIOA_PPUDR = (LED_A Or LED_B)

  ' Set the default state for the led 
  If (led_a_active) Then
    AT91C_PIOA_SODR = LED_A
  Else
    AT91C_PIOA_CODR = LED_A
  End If

  If (led_b_active) Then
    AT91C_PIOA_SODR = LED_B
  Else
    AT91C_PIOA_CODR = LED_B
  End If

End Sub


'-----------------------------------------------------------------------------
' * Function Name       : timer_handler
' * Object              : Handler for TC interrupt
' *---------------------------------------------------------------------------
Irq timer_handler()

  Dim dummy As Integer
  ' Clear status bit 
  dummy = AT91C_TC0_SR

  ' Toggle LED state 
  If (AT91C_PIOA_ODSR And LED_B) Then
    AT91C_PIOA_CODR = LED_B
  Else 
    AT91C_PIOA_SODR = LED_B
  End If

End Irq


'-----------------------------------------------------------------------------
' * Function Name       : configure_tc
' * Object              : Configure TC
' *---------------------------------------------------------------------------
Sub configure_tc()

    Dim dummy As Integer

    ' Enable periph clock for the PIO controller 
    AT91C_PMC_PCER = (1 << AT91C_ID_TC0)

    ' Enable the periph 
    ' Disable the clock and the interrupts 
    AT91C_TC0_CCR = AT91C_TC_CLKDIS
    AT91C_TC0_IDR = &HFFFFFFFF

    ' Clear status bit 
    dummy = AT91C_TC0_SR

    ' Set the Mode of the Timer Counter 
    AT91C_TC0_CMR = AT91C_TC_CLKS_TIMER_DIV5_CLOCK Or AT91C_TC_CPCTRG
    AT91C_TC0_RC = __conf_MCK  >> 12  ' MCKR divided by 1024 * 4 AT91B_MASTER_CLOCK
    
    ' Enable interrupts 
    ' Disable the interrupt on the interrupt controller 
    AT91C_AIC_IDCR = (1 << AT91C_ID_TC0)
    ' Save the interrupt handler routine pointer and the interrupt priority 
    ' AT91C_AIC_SVR[AT91C_ID_TC0] = timer_handler
    AT91C_AIC_SVR12 = AddressOf timer_handler ' AT91C_ID_TC0 = 12

    ' Store the Source Mode Register 
    ' AT91C_AIC_SMR[AT91C_ID_TC0] = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST
    AT91C_AIC_SMR12 = AT91C_AIC_SRCTYPE_INT_HIGH_LEVEL Or AT91C_AIC_PRIOR_LOWEST

    ' Clear the interrupt on the interrupt controller 
    AT91C_AIC_ICCR = (1 << AT91C_ID_TC0)

    AT91C_TC0_IER = AT91C_TC_CPCS

    ' Enable the interrupt on the interrupt controller 
   AT91C_AIC_IECR = (1 << AT91C_ID_TC0)

    ' Enable the LED B timer 
    If (led_b_active) Then
      ' Clock is started 
      AT91C_TC0_CCR = AT91C_TC_CLKEN
      ' Counter is reset and the clock is started 
      AT91C_TC0_CCR = AT91C_TC_SWTRG
    End If

End Sub

'----------------------------------------------------------------------------
' * Function Name       : dbgu_print_ascii
' * Object              : This function is used to send a string through the
' *                       DBGU channel (Very low level debugging)
' *--------------------------------------------------------------------------
Sub dbgu_print_ascii( buffer$ As String )
    Dim l As Integer
    Dim i As Integer

    i = 1
    l = Len(buffer$)
    Do While (i <= l) 
        Do While (Not CBool((AT91C_DBGU_CSR And AT91C_US_TXRDY)))
        Loop
        AT91C_DBGU_THR = ( Asc(Mid$(buffer$,i,1)) And &H1FF )
        i = i + 1
    Loop

End Sub


'----------------------------------------------------------------------------
' * Function Name       : dbgu_print_hex8
' * Object              : This function is used to print a 32-bit value in hex
' *---------------------------------------------------------------------------
Sub dbgu_print_hex8(value As Integer)

    Dim  c As Byte = 0
    Dim  shift As Byte  = 32 '= sizeof(unsigned long) * 8

    Call dbgu_print_ascii("&H")
    Do 
        shift = shift - 4
        Do While (Not CBool((AT91C_DBGU_CSR And AT91C_US_TXRDY)))
        Loop
        c = ((value >> shift) And &HF)
        If (c > 9) Then
            AT91C_DBGU_THR = ((Asc("A") + (c - 10)) And &H1FF)
        Else
            AT91C_DBGU_THR = ((Asc("0") + c) And &H1FF)
        End If
    Loop While (shift <> 0)
End Sub

'-----------------------------------------------------------------------------
' * Function Name       : configure_dbgu
' * Object              : Configure DBGU
' *---------------------------------------------------------------------------
'
' Re-configuring DBGU can lead to lost sync between PC and AT91SAM7-EK board.
' Since HBBR runtime is configuring the DBGU there is no need to do it again
'
Sub configure_dbgu ()

    ' Reset and disable receiver 
    AT91C_DBGU_CR = AT91C_US_RSTRX Or AT91C_US_RSTTX

    ' Disable interrupts 
    AT91C_DBGU_IDR = &HFFFFFFFF

    ' Configure PIOs for DBGU 
    AT91C_PIOA_ASR = AT91C_PA9_DRXD Or AT91C_PA10_DTXD
    AT91C_PIOA_BSR = 0
    AT91C_PIOA_PDR = AT91C_PA9_DRXD Or AT91C_PA10_DTXD

    ' === Configure serial link === 
    ' Define the baud rate divisor register [BRGR = MCK / (115200 * 16)]
    ' Default baud rate for HBBR Basic IDE is 38400
    AT91C_DBGU_BRGR = __conf_MCK / (38400 * 16)
    
    ' Define the USART mode 
    AT91C_DBGU_MR = AT91C_US_PAR_NONE Or AT91C_US_CHMODE_NORMAL

    ' Disable the RX and TX PDC transfer requests 
    AT91C_DBGU_PTCR = AT91C_PDC_RXTDIS
    AT91C_DBGU_PTCR = AT91C_PDC_TXTDIS

    ' Enable transmitter 
    AT91C_DBGU_CR = AT91C_US_TXEN

End Sub

'-----------------------------------------------------------------------------
' * Function Name       : wait
' * Object              : Tempo using jiffies (updated by PITC)
' *---------------------------------------------------------------------------
Sub wait (ms As Integer)

    Dim current_time As Integer
    Dim prev_jiffies As Integer
    Dim target_time  As Integer

    current_time = jiffies
    target_time = current_time + ms

    ' Handle the counter overflow 
    If (target_time < current_time) Then
        prev_jiffies = current_time
        Do While (prev_jiffies <= jiffies)
            prev_jiffies = jiffies
        Loop
    End If
    ' Loop until the target time is reached 
    Do While (jiffies < target_time)
    Loop

End Sub

Sub dump_CONF()
    Print #0, "MCK    :";__conf_MCK
    Print #0, "CSS    :";__conf_CSS
    Print #0, "PRES   :";__conf_PRES
    Print #0, "MAINCK :";__conf_MAINCK
    Print #0, "SLCK   :";__conf_SLCK
    Print #0, "PLLCK  :";__conf_PLLCK
    Print #0, "DIV    :";__conf_DIV
    Print #0, "MUL    :";__conf_MUL
    Print #0, "PCK    :";__conf_PCK
    Print #0, "UDPCK  :";__conf_UDPCK
    Print #0, "USBDIV :";__conf_USBDIV
End Sub

Sub Main()

    ' ==== Dump MOD configuration ====
    Call dump_CONF()

    ' ==== PITC configuration ====
    Call configure_pit()

    ' ==== Timer Counter configuration ====
    Call configure_tc()

    ' === BUTTON configuration (PIO in INPUT) ===
    Call configure_buttons()

    ' === LED configuration (PIO in OUTPUT) ===
    Call configure_leds()

    ' ==== DBGU configuration ====
    ' DBGU is configured by the HBBR runtime
    ' 
    ' Call configure_dbgu()

    Call dbgu_print_ascii("AT91SAM7S Getting Started program launched ...")
    Call dbgu_print_ascii(Chr$(CR))
    Call dbgu_print_ascii(Chr$(LF))
    Call dbgu_print_ascii("AT91SAM7S chip ID : ")
    Call dbgu_print_hex8(AT91C_DBGU_CIDR)
    Call dbgu_print_ascii(Chr$(CR))
    Call dbgu_print_ascii(Chr$(LF))

    ' Enable interrupts
    Call __hbbr_enable_irq()

    Do While (1)
        If (led_a_active)  Then
            ' Switch on the led
            Call wait(500)
            AT91C_PIOA_CODR = LED_A

            ' Switch off the led
            Call wait(500)
            AT91C_PIOA_SODR = LED_A
        End If
    Loop

End Sub