z80189 ZiLOG Semiconductor, z80189 Datasheet - Page 172

• Manufacturer Part Number: z80189
• Description: Z80180, Z8s180, Z8l180 Mpu Operation
• Manufacturer: ZiLOG Semiconductor

Phi ¸ 20
Timer Data
Register 0L
: TMDR0L (8)
Timer Reload
Register 0L
: RLDR0L (8)
control register. The PRT input clock for both channels is equal to the
system clock divided by 20.
Figure 63.
PRT Register Description
Timer Data Register (TMDR: I/O Address - CH0: 0CH, 0DH; CH1: 15H,
14H). PRT0 and PRT1 each contain 16-bit timer Data Registers (TMDR).
TMDR0 and TMDR1 are each accessed as low and high byte registers
(TMDR0H, TMDR0L and TMDR1H, TMDR1L). During RESET,
TMDR0 and TMDR1 are set to
TMDR is decremented once every twenty clocks. When TMDR counts
down to 0, it is automatically reloaded with the value contained in the
Reload Register (RLDR).
TMDR is read and written by software using the following procedures.
The read procedure uses a PRT internal temporary storage register to
Timer Data
Register 0H
: TMDR0H (8)
Timer Reload
Register 0H
: RLDR0H (8)
PRT Block Diagram
Internal Address/Data Bus
Timer Control
Register
: TCR (8)
Interrupt Register
FFFFH
Timer Data
Register 1L
: TMDR1L (8)
Phi ¸ 20
Timer Reload
Register 1L
: RLDR1L (8)
.
Family MPU User Manual
Timer Data
Register 1H
: TMDR1H (8)
Timer Reload
Register 1H
: RLDR1H (8)
UM005003-0703
TOUT
Z8018x
157