st2064b Sitronix Technology Corporation, st2064b Datasheet - Page 43

• Manufacturer Part Number: st2064b
• Description: 8 Bit Microcontroller With 64k Bytes Rom
• Manufacturer: Sitronix Technology Corporation

1
ST2064B has three power down modes: WAI-0, WAI-1 and
STP. The instruction WAI will enable either WAI-0 or WAI-1,
which is controlled by WAIT(SYS[2]). And the instruction
16.1 WAI-0 Mode:
If WAIT is cleared, WAI instruction makes MCU enter WAI-0
mode. In the mean time, the oscillator, interrupts,
timer/counter, and PSG are still working. On the other hand
CPU and the related instruction execution stop. All registers,
RAM, and I/O pins will retain the same states as those
before the MCU entered power down mode. WAI-0 mode
16.2 WAI-1 Mode:
If WAIT is set, WAI instruction makes MCU enter WAI-1
mode. In this mode, CPU stops, but the PSG, timer/counter
keep running if their clock sources are from OSCX. The
16.3 STP Mode:
STP instruction will force MCU to enter stop mode. In this
mode, MCU stops, but PSG, timer/counter won’ t stop if the
clock source is from OSCX. In power-down mode, MCU
Ver. 3.0
1
Address Name
6
6
LDA
STA
WAI
LDA
STA
WAI
$030
.
.
Bit 3: WSKP : System warm-up control bit
Bit 2: WAIT : WAI-0 / WAI-1mode select bit
P
P
O
O
#$00
<SYS
#$04
<SYS
W
W
SYS
1 = Warm-up to 16 oscillation cycles
0 = Warm-up to 256 oscillation cycles
1 = WAI instruction causes the chip to enter WAI-1 mode
0 = WAI instruction causes the chip to enter WAI-0 mode
E
E
R
R
D
R/W
D
R/W
; WAI 0 mode
; WAI 1 mode
O
O
W
W
Bit 7
XSEL
N
N
M
M
TABLE 16-1 System Control Register (SYS)
O
O
OSTP
Bit 6
D
D
E
E
S
S
XSTP
Bit 5
43/57
TEST
Bit 4
STP will enable STP mode in the same manner. WAI-0 and
WAI-1 modes can be waked up by interrupt. However, STP
mode can only be waked up by hardware reset.
can be waked up by reset or interrupt request even If user
sets interrupt disable flag I. In that case MCU will be waked
up but not entering interrupt service routine. If interrupt
disable flag is cleared (I=’ 0’ ), the corresponding interrupt
vector will be fetched and the service routine will be
executed. The sample program is shown below:
wake-up procedure is the same as for WAI-0. The
difference is that the warm-up cycles occurs when waking
from WAI-1. Sample program is shown as following:
can only be waked up by hardware reset, and the warm-up
cycles occurs at the same time.
WSKP
Bit 3
WAIT
Bit 2
Bit 1
-
LVDET
Bit 0
0000 00-0
Default
ST2064B
5/8/09