Table 14. Bit Access To The Led Cathode, Modem, And Triggers - ZiLOG eZ80F91 User Manual

eZ80F91 Development Kit
User Manual
34

Table 14. Bit Access to the LED Cathode, Modem, and Triggers

Function
Cathode Row 5
Cathode Row 4
Cathode Row 3
Cathode Row 2
Cathode Row 1
Modem RST
Trig 1
Trig 2
Operational Description
If bit 7 in the GPIO Output Control Register is 1, all of the GPIO lines are
configured as inputs. If this bit is 0, all of the GPIO lines are configured as
outputs.
Table 14 indicates the multiple register functions of the LED cathode,
modem, and triggers. This table shows the bit configuration for each cath-
ode bit. Bits 5, 6, and 7 do not carry any significance within the LED
matrix. These three bits are control bits for the modem reset, Trig1, and
Trig2 functions, respectively.
7
X
An LED display sample program is shipped with the eZ80F91 Develop-
ment Kit. Please refer to the eZ80Acclaim!™ Development Kits Quick
Start Guide (QS0020) or to the Tutorial section in the ZiLOG Developer
Studio—eZ80Acclaim! User Manual (UM0144).
Data Carrier Detect
The Data Carrier Detect (DCD) signal at D1 indicates that a good carrier
signal is being received from the remote modem.
Bit #
6 5 4 3
X
X
X
X
PRELIMINARY
2 1 0
X
X
X
UM014210-1003