GE IS220PRTDH1A IS220PRTDH1B RTD Input: 8 RTDs
Table 3-8 TMRCCR12 Bit Mapping
Field Bits Read or Write
Timer 2 Count TMRCCR12[31..16] Read Only
Timer 1 Count TMRCCR12[15..0] Read Only
When either field is read, the current count value is latched and returned. There
are two modes that determine how the count is latched depending on the setting
of the “Read Latch Select” bit in the Control Status Register (TCSR2). See the
TCSR2 register description for more information on these two modes.
3.3.7 Timer 3 Current Count Register (TMRCCR3)
The current count of Timer 3 may be read via the Timer 3 Current Count Register
(TMRCCR3), located at offset 0x24 from the address in BAR2. The mapping of bits
in this register is shown in Table 3-9.
Table 3-9 TMRCCR3 Bit Mapping
Field Bits Read or Write
Timer 3 Count TMRCCR3[31..0] Read Only
When this field is read, the current count value is latched and returned. There are
two modes that determine how the count is latched depending on the setting of
the “Read Latch Select” bit in the Control Status Register (TCSR2). See the TCSR2
register description for more information on these two modes.
3.3.8 Timer 4 Current Count Register (TMRCCR4)
The current count of Timer 4 may be read via the Timer 4 Current Count Register
(TMRCCR4), located at offset 0x28 from the address in BAR2. The mapping of bits
in this register is shown in Table 3-10.
Table 3-10 TMRCCR4 Bit Mapping
Field Bits Read or Write
Timer 4 Count TMRCCR4[31..0] Read Only
When this field is read, the current count value is latched and returned. There are
two modes that determine how the count is latched depending on the setting of
the “Read Latch Select” bit in the Control Status Register (TCSR2). See the TCSR2
register description for more information on these two modes.
3.3.9 Timer 1 IRQ Clear (T1IC)
The Timer 1 IRQ Clear (T1IC) register is used to clear an interrupt caused by
Timer 1. Writing to this register, located at offset 0x30 from the address in BAR2,
causes the interrupt from Timer 1 to be cleared. This can also be done by writing a
“0” to the appropriate “Timer x Caused IRQ” field of the timer Control Status
Register (TCSR1). This register is write only and the data written is irrelevant.
3.3.10 Timer 2 IRQ Clear (T2IC)
The Timer 2 IRQ Clear (T2IC) register is used to clear an interrupt caused by
Timer 2. Writing to this register, located at offset 0x34 from the address in BAR2,
causes the interrupt from Timer 2 to be cleared. This can also be done by writing a

“0” to the appropriate “Timer x Caused IRQ” field of the timer Control Status
Register (TCSR1). This register is write only and the data written is irrelevant.
3.3.11 Timer 3 IRQ Clear (T3IC)
The Timer 3 IRQ Clear (T3IC) register is used to clear an interrupt caused by
Timer 3. Writing to this register, located at offset 0x38 from the address in BAR2,
causes the interrupt from Timer 3 to be cleared. This can also be done by writing a
“0” to the appropriate “Timer x Caused IRQ” field of the timer Control Status
Register (TCSR1). This register is write only and the data written is irrelevant.
3.3.12 Timer 4 IRQ Clear (T4IC)
The Timer 4 IRQ Clear (T4IC) register is used to clear an interrupt caused by
Timer 4. Writing to this register, located at offset 0x3C from the address in BAR2,
causes the interrupt from Timer 4 to be cleared. This can also be done by writing a
“0” to the appropriate “Timer x Caused IRQ” field of the timer Control Status
Register (TCSR1). This register is write only and the data written is irrelevant.
3.4 Watchdog Timer
The V7768/V7769 provide a programmable Watchdog Timer (WDT) which can be
used to reset the system if software integrity fails.
3.4.1 WDT Control Status Register (WCSR)
The WDT is controlled and monitored by the WDT Control Status Register
(WCSR) which is located at offset 0x08 from the address in BAR2. The mapping of
the bits in this register is shown in Table 3-11.
Table 3-11 WCSR Bit Mapping
Field Bits Read or Write
SERR/RST Select WCSR[16] R/W
WDT Timeout Select WCSR[10..8] R/W
WDT Enable WCSR[0] R/W
All of these bits default to “0” after system reset. All other bits are reserved.
The “WDT Timeout Select” field is used to select the timeout value of the WDT as
shown in Table 3-12.
Table 3-12 Selecting Timeout Value of the WDT
Timeout WCSR[10] WCSR[9] WCSR[8]
135 s 0 0 0
33.6 s 0 0 1
2.1 s 0 1 0
524 ms 0 1 1
262 ms 1 0 0
131 ms 1 0 1
32.768 ms 1 1 0
2.048 ms 1 1 1