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\# Author Andy Pugh
\# Issued under the terms of the GPL v2 License or any later version
.TH hm2_uart_setup "3hm2" "2011-05-31" "LinuxCNC Documentation" "Hostmot2"
.SH NAME
hm2_uart_setup \- setup a Hostmot2 UART
.SH SYNTAX
.HP
int hm2_uart_setup(char *name, int bitrate, s32 tx_mode, s32 rx_mode){
.SH DESCRIPTION
\fBhm2_uart_setup\fR 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 maximimum 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) operaton, 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)
tx_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 attemped 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.
.SH RETURN VALUE
Returns0 on success and -1 on failure
.SH SEE ALSO
man hm2_uart_send, man hm2_uart_read
See src/hal/drivers mesa_uart.comp for an example usage.
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