Fujitsu FR81S User Manual
CHAPTER 27: UP/DOWN COUNTER
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : UP/DOWN COUNTER
FUJITSU SEMICONDUCTOR CONFIDENTIAL
FUJITSU SEMICONDUCTOR CONFIDENTIAL
10
4.2. Up/Down Count Register (UDCR0, UDCR1)
The bit configuration of the up/down count register is shown below.
This register operates as the counter for the up/down counter. The counter value can be checked by reading
these registers.
these registers.
UDCRH0 : Address 0F72
H
(Access : Half-word, Word)
UDCRH1 : Address 0F82
H
(Access : Half-word, Word)
bit15
bit14
bit13
bit12
bit11
bit10
bit9
bit8
D15
D14
D13
D12
D11
D10
D9
D8
Initial value
0
0
0
0
0
0
0
0
Attribute
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
UDCRL0 : Address 0F73
H
(Access : Byte, Half-word, Word)
UDCRL1 : Address 0F83
H
(Access : Byte, Half-word, Word)
bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
D7
D6
D5
D4
D3
D2
D1
D0
Initial value
0
0
0
0
0
0
0
0
Attribute
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
R,WX
As shown below, this register consists of a high-order byte and a low-order byte.
· Up/down count register high-order (UDCRH0, UDCRH1)
· Up/down count register low-order (UDCRL0, UDCRL1)
· Up/down count register low-order (UDCRL0, UDCRL1)
In the 8-bit mode, the high-order byte value is invalid.
The low-order byte of the up/down count register (UDCRL) must be read.
The low-order byte of the up/down count register (UDCRL) must be read.
Notes:
· This is a read-only register. To set a value in this register, transfer the reload compare register (RCR)
value to this register in the following procedure.
1. Write a value in the reload compare register (RCR)
2. Write the CSTR bit of the counter status register (CSR) to "0"
3. Write the CTUT bit of the counter control register (CCR) to "1"
2. Write the CSTR bit of the counter status register (CSR) to "0"
3. Write the CTUT bit of the counter control register (CCR) to "1"
· If the 16-bit mode is set with the M16E bit of the counter control register (CCR) (M16E=1), this register
must always be read by half-word access.
· If the 8-bit mode is set with the M16E bit of the counter control register (CCR) (M16E=0), the low-order
side of the up/down count register (UDCRL) must be read.
MB91520 Series
MN705-00010-1v0-E
1017