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ST90158 - STANDARD TIMER (STIM)
STANDARD TIMER (Cont’d)
9.3.5 Register Description
COUNTER HIGH BYTE REGISTER (STH)
R240 - Read/Write
Register Page: 11
Reset value: 1111 1111 (FFh)
Bit 7:0 = ST.[15:8]:
Counter High-Byte.
COUNTER LOW BYTE REGISTER (STL)
R241 - Read/Write
Register Page: 11
Reset value: 1111 1111 (FFh)
Bit 7:0 = ST.[7:0]:
Counter Low Byte.
Writing to the STH and STL registers allows the
user to enter the Standard Timer constant, while
reading it provides the counter’s current value.
Thus it is possible to read the counter on-the-fly.
STANDARD TIMER PRESCALER REGISTER
(STP)
R242 - Read/Write
Register Page: 11
Reset value: 1111 1111 (FFh)
Bit 7:0 = STP.[7:0]:
Prescaler.
The Prescaler value for the Standard Timer is pro-
grammed into this register. When reading the STP
register, the returned value corresponds to the
programmed data instead of the current data.
00h: No prescaler
01h: Divide by 2
FFh: Divide by 256
STANDARD
TIMER
CONTROL
REGISTER
(STC)
R243 - Read/Write
Register Page: 11
Reset value: 0001 0100 (14h)
Bit 7 = ST-SP:
Start-Stop Bit.
This bit is set and cleared by software.
0: Stop counting
1: Start counting
Bit 6 = S-C:
Single-Continuous Mode Select.
This bit is set and cleared by software.
0: Continuous Mode
1: Single Mode
Bit 5:4 = INMD[1:2]:
Input Mode Selection.
These bits select the Input functions as shown in
Section 9.3.2.2, when enabled by INEN.
Bit 3 = INEN:
Input Enable.
This bit is set and cleared by software. If neither
the STIN pin nor the CLOCK2 line are present,
INEN must be 0.
0: Input section disabled
1: Input section enabled
Bit 2 = INTS:
Interrupt Selection.
0: Standard Timer interrupt enabled
1: Standard Timer interrupt is disabled and the ex-
ternal interrupt pin is enabled.
Bit 1:0 = OUTMD[1:2]: Output Mode Selection.
These bits select the output functions as described
in Section 9.3.2.4.
70
ST.15 ST.14 ST.13 ST.12 ST.11 ST.10 ST.9
ST.8
70
ST.7
ST.6
ST.5
ST.4
ST.3
ST.2
ST.1
ST.0
70
STP.7 STP.6 STP.5 STP.4 STP.3 STP.2 STP.1 STP.0
70
ST-
SP
S-C
INMD
1
INMD
2
INEN INTS
OUTM
D1
OUTM
D2
INMD1 INMD2 Mode
00
Event Counter mode
01
Gated input mode
10
Triggerable mode
11
Retriggerable mode
OUTMD1 OUTMD2 Mode
00
No output mode
01
Square wave output mode
1x
PWM output mode
9