Zilog EZ80F91 - Manual (Page 37)

eZ80F91 Development Kit
User Manual
UM014220-0508 eZ80 Development Kit
32
Bits 0–6 in Table 9 are LED anode bits. They must be set High (1) and
their corresponding cathode bits, bits 0–4 in Table 15 , must be set Low (0)
to illuminate each of the LED’s, respectively.
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 15 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.
An LED display sample program is shipped with the eZ80F91 Develop-
ment Kit. Refer to eZ80Acclaim!
®
Development Kits Quick Start Guide
(QS0020) or to the Tutorial section in the Zilog Developer Studio II—
eZ80Acclaim!
®
User Manual (UM0144).
Table 15. Bit Access to the LED Cathode, Modem, and Triggers
Function
Bit #
7 6 5 4 3 2 1 0
Cathode Row 5 X
Cathode Row 4 X
Cathode Row 3 X
Cathode Row 2 X
Cathode Row 1 X
Modem RST X
Trig 1 X
Trig 2 X