Zilog eZ80F92 - Manual (Page 29)

eZ80F92 Development Kit
User Manual
UM013911-0607 Operational Description
25
These functions are memory-mapped with an address decoder based on
the Generic Array Logic GAL22lV10D (U15) device manufactured by
Lattice Semiconductor, and a bidirectional latch (U16). Additionally, U15
is used to decode addresses for access to the 7 x 5 LED matrix.
Table 6 lists the memory map addresses to registers that allow access to
the above functions. The register at address
800000h
controls GPIO Port
A Output Control and LED Anode register functions. The register at
address
800001h
controls the register functions for the LED cathode,
modem reset, and user triggers. Address
800002h
controls GPIO Port A
data.
Port A Emulation
GPIO Port A is emulated with the use of the GPIO Output Control Regis-
ter and the GPIO Data Register. If bit 7 in the GPIO Output Control Reg-
ister is 1, all of the lines on GPIO Port A are configured as input ports. If
this bit is 0, all of the lines on Port A are configured as output ports.
Table 7 lists the multiple functions of the register.
Table 6. LED and Port Emulation Addresses
Address Register Function Access
800000h LED Anode/GPIO Port output control WR
800001h LED Cathode/Modem/Trig WR
800002h GPIO Data RD/WR
Table 7. LED Anode/GPIO Port A Output Control Register
Function
Bit #
7 6 5 4 3 2 1 0
Anode Col 1 X
Anode Col 2 X
Anode Col 3 X