FreeCalypso > hg > freecalypso-tools
view target-utils/libbase/serio.S @ 497:74610c4f10f7
target-utils: added 10 ms delay at the end of abb_power_off()
The deosmification of the ABB access code (replacement of osmo_delay_ms()
bogus delays with correctly-timed ones, which are significantly shorter)
had one annoying side effect: when executing the poweroff command from
any of the programs, one last '=' prompt character was being sent (and
received by the x86 host) as the Calypso board powers off. With delays
being shorter now, the abb_power_off() function was returning and the
standalone program's main loop was printing its prompt before the Iota chip
fully executed the switch-off sequence!
I thought about inserting an endless tight loop at the end of the
abb_power_off() function, but the implemented solution of a 10 ms delay
is a little nicer IMO because if the DEVOFF operation doesn't happen for
some reason in a manual hacking scenario, there won't be an artificial
blocker in the form of a tight loop keeping us from further poking around.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 25 May 2019 20:44:05 +0000 |
parents | da6df2c626cf |
children |
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#include "ns16550.h" @ this module implements the elementary serial I/O operations .comm uart_base,4,4 .text .code 32 .global serial_out serial_out: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #0x11] @ Calypso UART non-std register SSR tst r3, #0x01 @ Tx FIFO full flag bne 1b strb r0, [r2, #NS16550_THR] bx lr .global serial_in_poll serial_in_poll: ldr r1, =uart_base ldr r2, [r1] ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_DR ldrneb r0, [r2, #NS16550_RBR] mvneq r0, #0 bx lr .global serial_flush serial_flush: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_TEMP beq 1b bx lr