SAA7380GP Philips Semiconductors, SAA7380GP Datasheet - Page 22

• Manufacturer Part Number: SAA7380GP
• Description: Error correction and host interface IC for CD-ROM ELM
• Manufacturer: Philips Semiconductors

Philips Semiconductors
7.7.21
This register is used to specify the configuration of the external buffer memory.
Table 19 MEMS register bits
Table 20 Host priority access
7.7.22
In the ATAPI mode writing to this register generates a host
interrupt. This interrupt is cleared when the host reads the
ATAPI status register or writes to the ATAPI command
register.
In the Sanyo and Oak compatibility modes writing to this
register has no effect.
7.7.23
This write only register is only available in the ATAPI
mode; it is the ATAPI status register and is used to transfer
status information to the ATAPI host.
1996 Apr 25
7
6
5
4
3
2
1
0
Error correction and host interface IC for
CD-ROM (ELM)
BIT 6
BIT
PRIORITY BITS
0
0
1
1
MEMS
ITRG
ASTAT
PRIORITY
PRIORITY
RFRSH
WIDTH
STATIC
CACHE
NAME
BIT 5
0
1
0
1
Host priority access. These bits specify the external memory accesses priority.
DRAM refresh rate. Setting this bit specifies a DRAM refresh rate of clock
frequency/400. Clearing this bit specifies a rate of clock frequency/200. WIth a 33 MHz
clock this bit should be set, while with a 16 MHz clock the bit should be clear.
DRAM width select. This bit should be set if the external DRAM has a nibble wide data
bus. If the data bus is byte wide then this bit should be clear.
SRAM/DRAM select. If the external buffer memory is DRAM then this bit should be
cleared. If the memory is SRAM this bit should be set.
CACHE memory select. If the internal cache is available then this bit should be clear.
Setting this bit to logic 1 indicates that there is no internal cache memory.
only one host access has highest priority
two successive host accesses have highest priority
three successive host accesses have highest priority
four successive host accesses have highest priority
22
Bit 7 of this register is the BSY bit and this is set by the
SAA7380 whenever;
On reset this register is set to (80H).
SAA7380 is the selected drive and the host writes to the
command register (ACMD)
The host writes the execute drive diagnostic command
(90h) to the command register
The host writes to the device control register (ADCTR)
and sets the SRST bit
There is a hardware reset.
DESCRIPTION
ACCESS
Preliminary specification
SAA7380