Intel IXP42X Personal Computer User Manual


 
Intel
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
September 2006 DM
Order Number: 252480-006US 395
General Purpose Input/Output (GPIO)—Intel
®
IXP42X product line and IXC1100 control plane
processors
12.4.7 GPIO Clock Register
(GPCLKR)
This register controls the use of GPIO15 and GPIO14 as clock outputs. GPOER defines
the output enable for the driver; this register controls both the clock dividers and a
MUX between the clock data and the data defined in GPOUTR.
17:15 GPIO13 Not used.
14:12 GPIO12
000 = Active High
001 = Active Low
010 = Rising Edge
011 = Falling Edge
1xx = Transitional
Resets to 000 – Active High
11:9 GPIO11 As per GPIO12
8:6 GPIO10 As per GPIO12
5:3 GPIO9 As per GPIO12
2:0 GPIO8 As per GPIO12
Register
GPIT2R (Sheet 2 of 2)
Bits Name Description
Register Name: GPCLKR
Hex Offset Address: 0xC800 4018 Reset Hex Value: 0x01100000
Register
Description:
This register controls the use of GPIO 15 and GPIO14 as clock sources.
Access: See below.
31 25 24 23 20 19 16 15 9 8 7 4 3 0
(Reserved)
Mx15
CLK1TC CLK1DC (Reserved)
Mx14
CLK0TC CLK0DC
Register
GPCLKR (Sheet 1 of 2)
Bits Name Description
31:25 Not used. Ignored on writes and driven logic 0 on reads.
24 MUX15
0 = Control from GPOUTR Register
1 = Clock output
Reset: 1
23:20 CLK1TC
Terminal count for a 4 bit up counter @ PCLK. An F in this field and the CLK1DC
field is a special case to provide PCLK/2.
Reset: 0x1
19:16 CLK1DC
Represents the number of counts for which clock output should be low.
Reset: 0x0
15:9 - Not used. Ignored on writes and driven logic 0 on reads.