Quatech RS-422 - Manual (Page 10)

With NO jumpers on J13 or J20 the mode selection is RCLK=TCLK. With
Jumpers installed on J13 or J20 the mode selection is RCLK=AUXIN.
2.3.4 TGL0_SEL1,0, TGL1_SEL1,0 (J15,14,22,21)
With NO jumpers on J15,14, or J22,21 the mode selection is TXEN=1. With
Jumpers installed on J14 or J21 and NO jumpers on J15 or J22, the mode selection is
TXEN=DTR. With Jumpers installed on J15 or J22 and NO jumpers on J14 or J21,
the mode selection is TXEN=RTS. With Jumpers installed on J15, J14 or J22, J21, the
mode selection is TXEN=”Auto Toggle”.
2.3.5 RXEN0_SEL, RXEN1_SEL (J16, 23)
With NO jumpers on J16 or J23 the mode selection is RXEN=1. With
Jumpers installed on J16 or J23 the mode selection is RCLK=!TXEN.
2.4 Clock Rate and Optional Registers
Figure 3 shows the jumper configuration as shipped from the factory, with two
spare jumpers applied in neutral positions. Remove one or both and apply as shown in
following subsections to set optional features.
SPAD
X4
X2
J2
J4
J5
Figure 3 --- Factory default clock rate and options settings
2.4.1 Enable Scratchpad Register (SPAD, J2)
In the default configuration, an Interrupt Status Register and an Options Register
(see page 10) replace the scratchpad (base address + 7) of each UART. If the SPAD
jumper is applied as in Figure 4, the UART scratchpad registers are enabled, and the
Interrupt Status Register and the Options Register are not available.
DSCLP-200/300 User's Manual 5