FreeCalypso > hg > freecalypso-tools
view target-utils/tf-breakin/payload.S @ 407:19e5a3e2f9c0
fcup-settime: moved time() retrieval a little closer to the output
A fundamental problem with all simple time transfer tools is that there is
always some delay between the time retrieval on the source system and that
transmitted time being set on the destination, and the resulting time
on the destination system is off by that delay amount. This delay cannot
be fully eliminated when working in a simple environment like ours,
but we should make our best effort to minimize it. In the present case,
moving the atinterf_init() call before the time() retrieval should make
a teensy-tiny improvement.
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 11 Aug 2018 21:52:17 +0000 |
| parents | e7502631a0f9 |
| children |
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.text .org 0 @ allow entry in Thumb state .code 16 bx pc nop .code 32 @ set CPSR like mot931c payload does msr CPSR_c, #0xd3 @ disable the watchdog ldr r1, =0xfffff802 mov r0, #0xf5 strh r0, [r1, #2] mov r0, #0xa0 strh r0, [r1, #2] @ MODEM UART ldr r6, =0xffff5800 @ wait for any previous output to flush out 1: ldrb r0, [r6, #5] tst r0, #0x20 beq 1b @ send our indication adr r1, outstr mov r2, #6 1: ldrb r0, [r1], #1 strb r0, [r6] subs r2, r2, #1 bne 1b @ wait for this output to go out to the TxD pin 1: ldrb r0, [r6, #5] tst r0, #0x40 beq 1b @ enable the Calypso boot ROM ldr r1, =0xFFFFFB10 mov r2, #0x0100 strh r2, [r1] @ jump to it! mov pc, #0 .ltorg outstr: .byte 2,2,2,'O','K',2