HD6432646 Hitachi, HD6432646 Datasheet - Page 660

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

17.3
17.3.1
PWCYR1/2, PWBFR1A/C/E/G, and PWBFR2A/B/C/D are 16-bit registers. These registers are
linked to the bus master by a 16-bit data bus, and can be read or written in 16-bit units. They
cannot be read by 8-bit access; 16-bit access must always be used.
17.3.2
PWCR1/2, PWOCR1/2, and PWPR1/2 are 8-bit registers that can be read and written to in 8-bit
units. These registers are linked to the bus master by a 16-bit data bus, and can be read or written
by 16-bit access; in this case, the lower 8 bits will always be read as H'FF.
626
Bus
master
Bus
master
Figure 17-9 8-Bit Register Access Operation (Bus Master
Figure 17-8 16-Bit Register Access Operation (Bus Master
Bus Master Interface
16-Bit Data Registers
8-Bit Data Registers
Internal data bus
Internal data bus
H
H
L
L
interface
interface
Bus
Bus
PWCR1
PWCYR1
PWCR1 (Upper 8 Bits))
PWCYR1 (16 Bits))
Module
data bus
Module
data bus