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fw/spi.c: explain why we probably can't reach fosc/2 = 4 MHz
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10
fw/spi.c
10
fw/spi.c
@ -24,6 +24,16 @@
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#define SCLK B, 8
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#define SCLK B, 8
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/*
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* According to simulation, signals from MCU to transceiver should already
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* suffer severe degradation * at fosc/4 = 2 MHz due to parasitic capacitance
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* (assumed to be 10 pF) and the series resistors (10 kOhm) of the voltage
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* dividers.
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*
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* fosc/2 = 4 MHz looks horrible in simulation and does not work reliably in
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* practice either.
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*/
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void spi_init(void)
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void spi_init(void)
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{
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{
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/* SPI mode 0, MSB first, fosc/4 */
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/* SPI mode 0, MSB first, fosc/4 */
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