AMD Geode SC1201 - Manual (Page 78)

78 AMD Geode™ SC1200/SC1201 Processor Data Book
General Configuration Block 32579B
3 BUS16 (16-Bit Wide Boot Memory). (Read Only) This bit reports the status of the BOOT16 strap (ball C8). If the BOOT16
strap is pulled high, at reset 16-bit access to ROM in the Sub-ISA interface is enabled. MCR[14] = 1 inverts the meaning of
this register.
0: 8-bit wide ROM.
1: 16-bit wide ROM.
2:1 Reserved. Write as read.
0 SDBE0 (Slave Disconnect Boundary Enable). Works in conjunction with the GX1 module’s PCI Control Function 2 Regis-
ter (Index 41h), bit 1 (SDBE1). Sets boundaries for when the GX1 module is a PCI slave.
SDBE[1:0]
00: Read and Write disconnect on boundaries set by bits [3:2] of the GX1 module’s PCI Control Function 2 register (Index
41h).
01: Write disconnects on boundaries set by bits [3:2] of the GX1 module’s PCI Control Function 2 register. Read discon-
nects on cache line boundary of 16 bytes.
1x: Read and Write disconnect on cache line boundary of 16 bytes.
This bit is reset to 1.
All PCI bus masters (including SC1200/SC1201 processor’s on-chip PCI bus masters, e.g., the USB Controller) must be dis-
abled while modifying this bit. When accessing this register while any PCI bus master is enabled, use read-modify-write to
ensure these bit contents are unchanged.
Offset 38h Interrupt Selection Register - INTSEL (R/W) Reset Value: 00h
This register selects the IRQ signal of the combined WATCHDOG and High-Resolution timer interrupt. This interrupt is shareable with
other interrupt sources.
7:4 Reserved. Write as read.
3:0 CBIRQ. Configuration Block Interrupt.
0000: Disable 0100: IRQ4 1000: IRQ8# 1100: IRQ12
0001: IRQ1 0101: IRQ5 1001: IRQ9 1101: Reserved
0010: Reserved 0110: IRQ6 1010: IRQ10 1110: IRQ14
0011: IRQ3 0111: IRQ7 1011: IRQ11 1111: IRQ15
Offset 39h-3Bh Reserved - RSVD
Offset 3Ch Device Identification Number Register - ID (RO) Reset Value: xxh
This register identifies the device. SC1200 = 04h. SC1201 = 05h.
Offset 3Dh Revision Register - REV (RO) Reset Value: xxh
This register identifies the device revision. See the AMD Geode™ SC1200/SC1201 Processor Specification Update document for value.
Offset 3Eh-3Fh Configuration Base Address Register - CBA (RO) Reset Value: xxh
This register sets the base address of the Configuration block.
15:6 Configuration Base Address. These bits are the high bits of the Configuration Base Address.
5:0 Configuration Base Address. These bits are the low bits of the Configuration Base Address. These bits are set to 0.
Table 4-2. Pin Multiplexing, Interrupt Selection, and Base Address Registers (Continued)
Bit Description