Global control registers

There are a few registers of miscellaneous purpose at 0xb0000000, called the system global control registers.

address	name	description
0xb0000000	PDID	product ID register
0xb0000004	PWRON	power-on settings register
0xb000000c	MFSEL1	Multi-function selection register 1
0xb0000010	MFSEL2	Multi-function selection register 2
0xb0000014	MISCPE
0xb000001c	GPIOP1PE	GPIO port 1 power source configuration register
0xb0000020	GPIOP2PE	GPIO port 2 power source configuration register
0xb0000024	GPIOP3PE	GPIO port 3 power source configuration register
0xb000002c	GPIOP5PE	GPIO port 5 power source configuration register
0xb0000030	GPIOP6PE	GPIO port 6 power source configuration register
0xb0000034	GPIOP7PE	GPIO port 7 power source configuration register
0xb0000038	SPSWC	serial port switch control register
0xb000003c	INTCR
0xb0000040	?	Related to GFXI
0xb000004c	XBCR
0xb0000050	HIFCR
0xb0000060	INTCR2
0xb0000108	ETSR

PDID

Reading the PDID register yields the chip ID, which encodes identifies the chip down to the revision. The following versions are known:

PDID	version
0x00926450	Z1
0x03926450	Z2
0x04926450	Z21
0x08926450	A1
0x09926450	A2
0x0a926450	A3

SPSWC

bit	description
0:1	Serial port mode (SPMOD)
2:31	unknown

SPMOD	description
0	snoop
1	takeover
2	direct to host serial port 2
3	reserved

INTCR

bit	description
6	VGAIOEN
13:14	UINC, USB 1.1 insertion control. (0x = high imp., 10 = drive 0, 11 = drive 1)

References

• List of registers: AMI, Dell
• MFSEL bit definitions
• MFSEL1 usage in ATEN USB driver
• SPSWC values in AMI U-Boot