HD64570 HITACHI [Hitachi Semiconductor], HD64570 Datasheet - Page 323

• Manufacturer Part Number: HD64570
• Description: Serial Communications Adaptor
• Manufacturer: HITACHI [Hitachi Semiconductor]

Bits 7 3: Reserved. These bits always read 0 and must be set to 0.
Bits 2 0 (ECKS2 ECKS0: Expand Clock Input Select): Selects the TCNT clock as shown
below. These bits are cleared at reset.
ECKS2, ECKS1, ECKS0 = 0, 0, 0: TCNT clock rate = BC
ECKS2, ECKS1, ECKS0 = 0, 0, 1: TCNT clock rate = BC/2
ECKS2, ECKS1, ECKS0 = 0, 1, 0: TCNT clock rate = BC/4
ECKS2, ECKS1, ECKS0 = 0, 1, 1: TCNT clock rate = BC/8
ECKS2, ECKS1, ECKS0 = 1, 0, 0: TCNT clock rate = BC/16
ECKS2, ECKS1, ECKS0 = 1, 0, 1: TCNT clock rate = BC/32
ECKS2, ECKS1, ECKS0 = 1, 1, 0: TCNT clock rate = BC/64
ECKS2, ECKS1, ECKS0 = 1, 1, 1: TCNT clock rate = BC/128
Notes: 1.
Bit name
Read/Write
Initial value
2.
Bit 7 to bit 3 are reserved.
These bits always read 0 and must be set to 0.
BC (base clock) is obtained by dividing system
clock
—
—
by eight.
7
0
*1
—
—
6
0
*1
—
—
5
0
*1
—
—
4
0
*1
—
—
3
0
*1
ECKS2
R/W
2
0
Rev. 0, 07/98, page 307 of 453
Expand clock input select
000: BC
001: BC /2
010: BC /4
011: BC /8
100: BC /16
101: BC /32
110: BC /64
111: BC /128
ECKS1
R/W
1
0
*2
*2
*2
*2
*2
*2
*2
*2
ECKS0
R/W
0
0