FreeCalypso > hg > freecalypso-tools
annotate target-utils/buzplayer/timer.c @ 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> |
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| date | Sat, 25 May 2019 20:44:05 +0000 |
| parents | e3d40f49d8c4 |
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1 /* |
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2 * FreeCalypso buzzer "melodies" have times measured in TDMA frames, |
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3 * as that is the time unit in the main firmware which will ultimately |
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4 * play them. In this standalone buzzer player we simulate TDMA frame |
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5 * timing by programming Calypso TIMER1 with the period of 1875, and |
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6 * we detect timer overflow (one virtual TDMA frame time having passed) |
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7 * by polling the read register to avoid the need for interrupt handling |
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8 * infrastructure. |
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9 */ |
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10 |
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11 #include "types.h" |
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12 #include "timer.h" |
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13 |
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14 void |
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15 timer_init() |
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16 { |
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17 TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE; |
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18 TIMER1_REGS.load = 1875; |
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19 TIMER1_REGS.cntl = CNTL_CLOCK_ENABLE | CNTL_AUTO_RELOAD | CNTL_START; |
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20 } |
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21 |
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22 void |
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23 wait_for_tdma_frame() |
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24 { |
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25 u16 read1, read2; |
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26 |
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27 read1 = TIMER1_REGS.read; |
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28 for (;;) { |
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29 read2 = TIMER1_REGS.read; |
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30 if (read2 > read1) |
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31 return; |
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32 read1 = read2; |
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33 } |
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34 } |
