962b3eb40c
This adds support for JTAG programming by bitbanging GPIOs exposed on
the RaspberryPi's expansion header.
Tested by connecting directly to an STM32VLDiscovery board, without any
additional circuity. I observed maximum about 4MHz on the TCK pin with an
old analogue 'scope and about 100kHz when setting the speed to 100kHz.
Busyloop waiting is needed because even with a single 0ns nanosleep call
(with FIFO priority) it lowers the TCK speed to ~30kHz which is way too low
to be useful.
The speed testing with adapter_khz 2000 gave the following results:
sudo chrt -f 1 nice -n -19 ./src/openocd \
-f interface/raspberrypi-native.cfg \
-c "set WORKAREASIZE 0x2000" \
-f target/stm32f1x.cfg -c "adapter_khz 2000"
wrote 131072 bytes from file random.bin in 3.973677s (32.212 KiB/s)
dumped 131072 bytes in 1.445699s (88.538 KiB/s)
This is 3.7 times faster for writing and 14.3 times faster for reading
compared to the generic sysfsgpio driver; probably the writing speed is
limited by the target itself here and reading speed might be considerably
higher too with appropriate connection and a capable target.
BCM2835 name is choosen over BCM2708 because the published peripherals
datasheet uses the particular model name and not family name.
Change-Id: Ib78168be27f53c2a3c88c3dd8154d1190c318c78
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/758
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
34 lines
951 B
INI
34 lines
951 B
INI
#
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# Config for using Raspberry Pi's expansion header
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#
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# This is best used with a fast enough buffer but also
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# is suitable for direct connection if the target voltage
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# matches RPi's 3.3V and the cable is short enough.
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#
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# Do not forget the GND connection, pin 6 of the expansion header.
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#
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interface bcm2835gpio
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# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
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# These depend on system clock, calibrated for stock 700MHz
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# bcm2835gpio_speed SPEED_COEFF SPEED_OFFSET
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bcm2835gpio_speed_coeffs 113714 28
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# Each of the JTAG lines need a gpio number set: tck tms tdi tdo
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# Header pin numbers: 23 22 19 21
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bcm2835gpio_jtag_nums 11 25 10 9
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# If you define trst or srst, use appropriate reset_config
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# Header pin numbers: TRST - 26, SRST - 18
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# bcm2835gpio_trst_num 7
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# reset_config trst_only
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# bcm2835gpio_srst_num 24
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# reset_config srst_only srst_push_pull
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# or if you have both connected,
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# reset_config trst_and_srst srst_push_pull
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