Rainbow Electronics AT75C310 - Manual (Page 127)

AT75C310
127
B fiqvec ; FIQ
; -----------------------------------------------------------------------------
; Entry point.
;-----------------------------------------------------------------------------
InitReset
; Setup the SVC mode and stack pointer on the top of the internal RAM
mov rO, #ARM - MODE_SVC:OR:I_BIT:OR:F_BIT ; No interrupts
msr cpsr, rO
ldr r13, =RAM-LIMIT
;------------------------------------------------------------------------------
; Configure USARTO with the following parameters:
; Baud Rate 9600
; Mode: 1 Stop bit, Even Parity, 8 Data Bits, Clock = MCKI
; Channel = Normal Mode
;------------------------------------------------------------------------------
ldr rl, USARTO-CR-Reg ; Disable and Reset the Transmitter and Receiver
ldr r2, = OXAC
str r2, [r1]
ldr rl, USARTO_MR-Reg ; Set up the mode register with the
ldr r2, = OXCO ; parameters given above.
str r2, [r1]
ldr rl, USARTO_ID_Reg ; Disable All Interrupts
ldr r2, = Ox7FF
str r2, [r1]
ldr rl, USARTO_BR_Reg ; Setup the Baud Rate to 9600bps
ldr r2, = Ox9C
str r2, [r1]
ldr rl, USARTO_CR.Reg ; Enable the transmitter and receiver
ldr r2, = Ox5O
str r2, [r1]
;-----------------------------------------------------------------------------
; Read Modem Status and check that DSR is set. If it is not set then remap
;-----------------------------------------------------------------------------
ldr rl, USARTO-ModS_Reg
ldr r2, [rl]
tst r2, #Ox2O
beq remap
;-----------------------------------------------------------------------------
; Set RTS which indicates to the other end that we have seen the DSR and can proceed.
;-----------------------------------------------------------------------------
ldr rl, USARTO_ModC_Reg
ldr r2, =OxO2
str r2, (r1]
;-----------------------------------------------------------------------------
; Setup a value in r6 for the TIMEOUT. If this value goes to zero then this
; code performs a REMAP booting from CSO.
;-----------------------------------------------------------------------------
ldr r6, = WAIT_TIME
;-----------------------------------------------------------------------------
; Read the Initial sequence from the USART. The code will branch to REMAP if
; it has to wait for longer than approx 3 secs, or if any of the received
; characters are incorrect.
;---------------------------------------------------------------------------