vsc055xkm-01 Maxim Integrated Products, Inc., vsc055xkm-01 Datasheet - Page 96

• Manufacturer Part Number: vsc055xkm-01
• Description: Enhanced I?c Backplane Controller
• Manufacturer: Maxim Integrated Products, Inc.

3.2.85 CEh: General-Purpose Timer Count 2 (GPTC2)
3.2.86 CFh: General-Purpose Timer Enable (GPTE)
Revision 4.1
January 2008
The following table shows the bit assignments for the General-Purpose Timer Count 2 register.
The following table shows the bit assignments for the General-Purpose Timer Enable register.
Register Name:
Address:
Reset Value:
Bit
7:0
Register Name:
Address:
Reset Value:
Bit
7:1
0
Bit Label
TC23-16
Bit Label
RES
GPTE
GPTC2
CEh
0000_0000b
GPTE
CFh
0000_0000b
Access
R
R/W
Access
R/W
Description
Reserved.
General-Purpose Timer Enable
This bit enables the general-purpose timer to down count and generate an
interrupt when the timer reaches zero. The general-purpose timer down counts
using a clock source that is a divide-by-three of the core clock (8.0 MHz to
12.5 MHz), resulting in a timer count resolution of 375 ns to 240 ns.
When the timer initial count is set to all 1s, the maximum timeout is greater
than four seconds when using a 12.5 MHz core clock.
When the 24-bit timer reaches a value of zero, the interrupt output of the
VSC055-01 is asserted. The timer then re-loads with the initial count value
found in the GPTC0, GPTC1, and GPTC2 registers and begins counting down
again. Writing a value of FFh to the BCIS register clears this interrupt.
After a reset or power on, this bit is cleared, disabling the timer and timer
interrupt.
Description
Timer Count
These eight bits are part of the 24-bit general-purpose timer down counter
initial count value.
Writing to this register causes the timer to update and initiate a countdown from
the new value if the timer has been enabled in the GPTE register.
Clearing this register, along with the GPTC0 and GPTC1 registers, stops the
down counter and disables the interrupt generation logic.
After a reset or power on, these bits are cleared.
96 of 133
VSC055-01
Data Sheet