hm2_uart_setup - setup a Hostmot2 UART
#include <hostmot2-serial.h>
int hm2_uart_setup(char *name, int bitrate, s32 tx_mode, s32 rx_mode){ |
hm2_uart_setup Setup the bitrate for the UART named "name". "name" is a unique string given to each UART during hostmot2 setup. The names of the available UARTs are printed to standard output during the driver loading process and take the form: hm2_<board name>.<board index>.uart.<index> For example hm2_5i23.0.uart.0 The minimum bitrate is approximately 50bps, and the maximum around the FPGA frequency, 48MHz for a 5i23. The UART function allows different RX and TX bitrates, but that is not currently supported by this driver
tx_mode is bit
mask defined in the Hostmot2 regmap: Bit 0..3 = TXEnable
delay. TXEnable delay specifies the transmit data
holdoff time from the TXenable signal valid state. This is
used for
RS-485 (half duplex) operation, to delay transmit data until
the driver
is enabled, allowing for driver enable delays, isolation
barrier delays
etc. Delay is in units of ClockLow period. Bit 4 =
FIFOError, it indicates that a host push has overflowed the
FIFO
(Mainly for driver debugging) Bit 5 = DriveEnableAuto, When
set, enables Drive when any data is in FIFO or
Xmit Shift register,removes drive when FIFO and Xmit shift
register
are empty. Bit 6 = DriveEnableBit, If DriveEnableAuto is 0,
controls Drive (
for software control of Xmit drive)
rx_mode is bit
mask defined in the Hostmot2 regmap: Bit 0 = FalseStart bit
Status, 1 = false start bit detected Bit 1 = OverRun Status,
1 = overrun condition detected (no valid stop bit) Bit 2 =
RXMaskEnable, 1= enable RXMask for half duplex operation,
0 = ignore RXMask Bit 4 = FIFOError, indicates that a host
read has attempted to read more
data than available. (mainly for driver debugging) Bit 5 =
LostDataError, indicates that data was received with no room
in FIFO,
therefore lost Bit 6 = RXMask, RO RXMASK status Bit 7 = FIFO
Has Data
rx_mode and tx_mode registers are currently write-only. There should possibly be a get-status function.
To write only to the tx_mode DriveEnable bit call this function with the bitrate unchanged and -1 as the rx_mode To change bitrate without altering mode settings send -1 to both modes.
Returns0 on success and -1 on failure
man hm2_uart_send, man hm2_uart_read See src/hal/drivers mesa_uart.comp for an example usage.