ST62T35B ST Microelectronics, ST62T35B Datasheet - Page 49

• Manufacturer Part Number: ST62T35B
• Description: (ST62E35B / ST62T35B) 8-BIT OTP/EPROM MCUs
• Manufacturer: ST Microelectronics

4.3.5 CONTROL REGISTERS
Status Control Register 1 (SCR1)
Address: E8h - Read/Write/Clear only
Bits 7 & 6 = PSC2..PSC1 . Clock Prescaler . These
bits define the prescaler options for the prescaler
to the Counter Register according to the following
table.
The Prescaler must be disabled (PSC2 = 0, PSC1
= 0) before a new prescaler factor is set if the
counter is running (after a hardware reset the
prescaler is automatically disabled).
To avoid inconsistencies in timing, the prescaler
factor should be set first, and then the counter
started.
Bit 5 = RELOAD. Reload enabled. When set this
bit enables reload from RLCP register into CT reg-
ister. On the contrary, if RELOAD is cleared,
RLCP is used as target for capture from the coun-
ter CT register.
Bit 4 = RUNRES . Run/Reset . This bit enables the
RUN or RESET operation of the ARTIMER.
If 0, the counter CT is cleared to zero, and is
stopped. Setting this bit to 1 permits the startup of
the counter, and enables the synchronisation cir-
cuits for the timer inputs CP1 and CP2.
Bit 3 = OVFIEN . Overflow Int. Enable . The Over-
flow Interrupt is masked when this bit is 0.
Setting the bit to 1 enables the overflow flag to set
the ARTIMER interrupt.
Bit 2 = OVFFLG. When this bit is 0, no overflow
has occurred since the last clear of this bit. If the
bit is at 1, an overflow has occurred.
This bit cannot be set by program, only cleared.
Bit 1 = OVFMD. The Overflow Output mode is set
by this bit; when 0, the overflow output is run in set
mode (OVF will be set on the first overflow event,
and will be reset when OVFFLG is cleared). When
1 the overflow output is in toggle mode; OVF tog-
gles its state on every overflow event (independ-
ent to the state of OVFFLG).
PSC2 PSC1 RELOAD RUNRES OVFIEN OVFFLG OVFMD
PSC2
7
0
0
1
1
PSC1
0
1
0
1
Clock Disabled (prescaler and counter
stopped
Prescale by 1
Prescale by 4
Prescale by 16
Function
0
-
Bit 0 = This bit is reserved and must be set to 0.
Status Control Register 2 (SCR2)
Address: E1h - Read/Write/Clear only
Bit 7 = Reserved. Must be kept cleared.
Bit 6 = CP1ERR . CP1 Error Flag . This bit is set to
1 if a new CP1 event has taken place since
CP1FLG was set to signal an error condition, it is 0
if there has been no event.
It is recommended to clear CP1ERR at any time
that CP1FLG is cleared, as further CP1 events
cannot be recognised if CP1ERR is set. This bit
cannot bet set by write, only cleared.
Bit 5 = CP2ERR . CP1 Error Flag . This bit is set to
1 if a new CP2 event has taken place since
CP2FLG was set to signal an error condition, it is 0
if there has been no event.
It is recommended to clear CP2ERR at any time
that CP2FLG is cleared, as further CP2 events
cannot be recognised if CP2ERR is set. This bit
cannot bet set by write, only cleared.
Bit 4 = CP1IEN. CP1 Interrupt Enable . CP1 The
Capture 1 Interrupt is masked when this bit is 0.
Setting the bit to 1 enables the CP1 event flag
CP1FLG to set the ARTIMER interrupt.
Bit 3 = CP1FLG. CP1 Interrupt Flag . When this bit
is 0, no CP1 event has occurred since the last
clear of this bit. If the bit is at 1, a CP1 event has
occurred.
This bit cannot be set by program, only cleared.
Bit 2 = CP1POL. CP1 Edge Polarity Select .
CP1POL defines the polarity for triggering the
CP1 event.
A 0 defines the action on a falling edge on the CP1
input, a 1 on a rising edge.
Bit 1 & 0 = RLDSEL2..RLDSEL1 . Reload Source
Select . These bits define the source for the reload
events; they do not affect the operation of the cap-
ture modes.
RLDSEL2 RLDSEL1
7
-
0
0
1
1
CP1ERR CP2ERR CP1IEN CP1FLG CP1POL RLDSEL2 RLDSEL1
0
1
0
1
Reload and startup triggered by
RUNRES
Reload triggered by every CP1
event
Reload triggered by every CP2
event
Reload disabled
ST62T35B/E35B
Function
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