101-0775 Rabbit Semiconductor, 101-0775 Datasheet - Page 174

• Manufacturer Part Number: 101-0775
• Description: CARD CPU SR9160 512K SRAM SMRTST
• Manufacturer: Rabbit Semiconductor

Specifications of 101-0775

• Accessory Type: Smart Star CPU Card
• For Use With/related Products: SR9160
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The slots on the Smart Star backplane are accessed as external registers via the Rabbit
2000’s assembly IOE prefix or via standard Rabbit BIOS functions. More convenient
functions specific to the Smart Star control system have been written to provide more flex-
ibility; for example, there is now a provision for the automatic update of shadow registers
for each slot and for each register.
The Smart Star design routes four address bits to each slot, providing 16 register addresses
for each slot. These bits are passed through as bits 0–3 of the register address. The slot
number itself is assigned to bits 6–8 of the address. In addition, the backplane design
requires that bits 13 and 14 be high and that bit 9 be low. The simplest way to enforce this
is to use a base address of 0x6000. Table D-1 provides the address layout for accessing the
Smart Star slots, where Sn is the binary representation of the slot number (0–6), Rn is the
binary representation of the register numbers (0–15), and X means the value does not matter.
This bit mapping of the external register address provides the register addresses for each
slot as listed in Table D-2.
174
A15 A14 A13 A12 A11 A10
0
1
1
Table D-1. Smart Star External Register Address Bitmap
0
Table D-2. Slot External Register Addresses
X
Slot Number
X
0
1
2
3
4
5
6
A9
0
A8
S2
Address Range
0x60C0–0x60CF
0x6000–0x600F
0x6040–0x604F
0x6080–0x608F
0x6100–0x610F
0x6140–0x614F
0x6180–0x618F
A7
S1
A6
S0
A5
X
A4
X
A3
R3
Smart Star (SR9000)
A2
R2
A1
R1
A0
R0