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uart_set_baudrate should return actual rate set even in case of out of range parameters

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graham sanderson 2021-01-28 10:01:12 -06:00 committed by Luke Wren
parent 5ca82a9467
commit 16df9f8a95
2 changed files with 11 additions and 8 deletions
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1
src/common/pico_base/include/pico/error.h
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@ -16,6 +16,7 @@ enum {
PICO_ERROR_TIMEOUT = -1, PICO_ERROR_TIMEOUT = -1,
PICO_ERROR_GENERIC = -2, PICO_ERROR_GENERIC = -2,
PICO_ERROR_NO_DATA = -3, PICO_ERROR_NO_DATA = -3,
PICO_ERROR_OUT_OF_RANGE = -4,
}; };
#endif #endif

18
src/rp2_common/hardware_uart/uart.c
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@ -75,23 +75,25 @@ uint uart_set_baudrate(uart_inst_t *uart, uint baudrate) {
uint32_t baud_rate_div = (8 * clock_get_hz(clk_peri) / baudrate); uint32_t baud_rate_div = (8 * clock_get_hz(clk_peri) / baudrate);
uint32_t baud_ibrd = baud_rate_div >> 7; uint32_t baud_ibrd = baud_rate_div >> 7;
uint32_t baud_fbrd = ((baud_rate_div & 0x7f) + 1) / 2; uint32_t baud_fbrd = ((baud_rate_div & 0x7f) + 1) / 2;
invalid_params_if(UART, (baud_ibrd > 65535) || (baud_ibrd == 0));
if (baud_ibrd == 0) {
baud_ibrd = 1;
baud_fbrd = 0;
} else if (baud_ibrd >= 65535) {
baud_ibrd = 65535;
baud_fbrd = 0;
}
// Load PL011's baud divisor registers // Load PL011's baud divisor registers
uart_get_hw(uart)->ibrd = baud_ibrd; uart_get_hw(uart)->ibrd = baud_ibrd;
if (baud_ibrd == 65535) { uart_get_hw(uart)->fbrd = baud_fbrd;
uart_get_hw(uart)->fbrd = 0;
} else {
uart_get_hw(uart)->fbrd = baud_fbrd;
}
// PL011 needs a (dummy) line control register write to latch in the // PL011 needs a (dummy) line control register write to latch in the
// divisors. We don't want to actually change LCR contents here. // divisors. We don't want to actually change LCR contents here.
hw_set_bits(&uart_get_hw(uart)->lcr_h, 0); hw_set_bits(&uart_get_hw(uart)->lcr_h, 0);
// See datasheet // See datasheet
uint baud = (4 * clock_get_hz(clk_peri)) / (64 * baud_ibrd + baud_fbrd); return (4 * clock_get_hz(clk_peri)) / (64 * baud_ibrd + baud_fbrd);
return baud;
} }
/// \end::uart_set_baudrate[] /// \end::uart_set_baudrate[]