ST62T46B/E46B
TIMER 1& 2 (Cont’d)
4.2.4 TIMER 1 Registers
Timer Status Control Register (TSCR)
Address: 0D4h — Read/Write
7
0
TMZ ETI
-
-
PSI PS2 PS1 PS0
Bit 7 = TMZ: Timer Zero bit
A low-to-high transition indicates that the timer
count register has decrement to zero. This bit
must be cleared by user software before starting a
new count.
Bit 6 = ETI: Enable Timer Interrup
When set, enables the timer interrupt request. If
ETI=0 the timer interrupt is disabled. If ETI=1 and
TMZ=1 an interrupt request is generated.
Bit 5 = Reserved. Must be set to 1.
Bit 4 = Do not care
Data sent to the timer output when TMZ is set high
(output mode only). Input mode selection (input
mode only)
Bit 3 = PSI: Prescaler Initialize Bit
Used to initialize the prescaler and inhibit its count-
ing. When PSI=“0” the prescaler is set to 7Fh and
the counter is inhibited. When PSI=“1” the prescal-
er is enabled to count downwards. As long as
PSI=“0” both counter and prescaler are not run-
ning.
Bit 2, 1, 0 = PS2, PS1, PS0: Prescaler Mux. Se-
lect. These bits select the division ratio of the pres-
caler register.
Table 13. Prescaler Division Factors
PS2
PS1
PS0 Divided by
0
0
0
1
0
0
1
2
0
1
0
4
0
1
1
8
1
0
0
16
1
0
1
32
1
1
0
64
1
1
1
128
Timer Counter Register (TCR)
Address: 0D3h — Read/Write
7
0
D7 D6 D5 D4 D3 D2 D1 D0
Bit 7-0 = D7-D0: Counter Bits.
Prescaler Register PSC
Address: 0D2h — Read/Write
7
0
D7 D6 D5 D4 D3 D2 D1 D0
Bit 7 = D7: Always read as ”0”.
Bit 6-0 = D6-D0: Prescaler Bits.
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