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RE: AGAIN: Serial ports non-standard speeds



Hi,

If you need exactly 500 kHz you must use an external baudrate
clock. This is achieved by:

1. Set up the R_ALT_SER_BAUDRATE register to select extern
baud rate clock for receiver and transmitter of the desired
serial port. 
2. Enable external clock in R_GEN_CONFIG_II
3. Conect a 500 kHz clock to pin PB6.

The best way to add external baud rate support in software 
is to add a new ioctl to the serial port driver.


/Mikael



-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com
To: dev-etrax
Sent: 2002-07-11 11:11
Subject: AGAIN: Serial ports non-standard speeds

Hi all,

Maybe I did not explain very well our needs. The ETRAX 100 LX datasheet 
states that the chip has 4 asynchronous serial ports with
a) Internal Baudrate programmable from 48 Hz. to 1,5625 MHz
b) External Baudrate up to 3,125 Mhz.
c) Fixed Baudrates from 300 Hz. to 1843.5 kHz plus a non-standard
baudrate 
at 6.25 MHz

Well, only the fixed baudrates seem to be available in Linux. We need to

use 500 kHz.
What should we do in order to have an external baudrate? It seems the
only 
way to obtain exactly 500 kHz.

Thanks to all.

   Rafael