Quatech DS-200/300 user manual Options Register bit definitions

5		OR5		not used
4		OR4		not used
3		OR3		not used
2		OR2		not used
1		RR1		rate register bit 1
0		RR0		rate register bit 0
Figure 9--- Options Register bit definitions
		WRITE			READ
	ID1		ID0		ID1	ID0
	0		0		0	0
	0		1		0	1
	1		0		0	1
	1		1		1	0

Figure 10 --- ID bit write/read table

The rate register allows software applications to check and set the data rate multiplier. As long as the SW jumper is installed in jumper block J9, the DS-200/300 gets the data rate multiplier from the value stored in the rate register portion of the OR.

RR1	RR0	DATA RATE	UART CLOCK SPEED	MAX DATA RATE
		MULTIPLIER
0	0	x1	1.8432 MHz	115.2 kbaud
0	1	x2	3.6864 MHz	230.4 kbaud
1	0	x4	7.3728 MHz	460.8 kbaud *
1	1	x8	14.7456 MHz	921.6 kbaud *

* - with 16750 UART only

Figure 11 --- Rate Register bit definition

A read of this register will return the value for the data rate multiplier that the board is actually operating at, regardless of what is written to the register. In other words, even when the data rate multiplier is being controlled by the hardware jumper setting, the value read from this register will correspond to that hardware jumper setting. This allows applications software to detect the actual rate at which the board is running.

At power on and reset, the rate register is initialized at 00. This means that the DS-200/300 will power up in the x1 mode as long as the SW jumper is installed. The DS-200/300 ships from the factory with the SW jumper installed.

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