Specifications

Counter/Timers
PROGRAMMABLE REGISTERS
Four separately addressable registers are used for communication with
the TCU. The TMD (Timer Mode) register specifies the operation of
the three counter/timers. The TMD is a write-only register. The other
three bidirectional registers, called the Count and Status registers, are
used to write the count to the counter/timers and read the count and
status back.
The base I/O address of the TCU registers is defined by the OPHA
and TULA registers. OPHA is programmed with the high byte and
TULA with the low byte of the 16-bit address. Refer to Chapter 6 for
a complete discussion on the V40 configuration registers, including
OPHA and TULA. The address of the TCU registers, relative to the
base address, is shown in Table 7-1.
Table 7-1
TCU Register Addressing.
Address Register Operation Page Number
Base + 0 TCT0 Count Read/Write 7-12
Base + 0 TCT0 Status Read 7-12
Base + 1 TCT1 Count Read/Write 7-12
Base + 1 TCT1 Status Read 7-12
Base + 2 TCT2 Count Read/Write 7-12
Base + 2 TCT2 Status Read 7-12
Base + 3 TMD Write 7-8
7-7