tsc693e ETC-unknow, tsc693e Datasheet - Page 13

• Manufacturer Part Number: tsc693e
• Description: Memory Controller
• Manufacturer: ETC-unknow

Selection of RAM size is performed by programming the Memory Configuration
Register (see page 52). The default value after system reset is 256 Kbytes.
It is possible to divide the selected RAM size into one, two, four, or eight equally sized
memory blocks by programming the Memory Configuration Register. The default value
after system reset is one block. A memory block is a block composed of 32-bit data,
parity bit, and 7-bit check code and controlled with one chip select signal.
The MEC provides eight RAM memory chip selects. One, two, four, or eight chip
selects are possible to use corresponding to the programmed number of memory blocks.
The default value after system reset is one chip select. The MEC also provides two
additional RAM chip selects to handle memory redundancy. See paragraph 3.10.
In the RAM area a store subword (byte or half-word) is implemented as a read-modify-
write since check bits must be generated over the whole word, see Figure 3 below.
3.2.2.1. Extended RAM
In addition to the nominal RAM area, an extended RAM area is reserved in the MEC
memory map. The MEC does not provide any chip select signals for the extended RAM
area, i.e. address decoding must be implemented with external logic. The extended
RAM area is BUSRDY* controlled with the same number of waitstates as the RAM
MATRA MHS
Rev. D (10 Apr. 97)
D (31:0),DPARIO
RAM Size
256 Kbyte 8k chips
512 Kbyte 16k chips
1 Mbyte
2 Mbyte
4 Mbyte
8 Mbyte
16 Mbyte
32 Mbyte
Table 1 - Memory sizes and organizations, using 8-bit wide memory-chips
A (31:0)
CB(6:0)
CLK2
CLK
Store Address
Chip org.
8 CS used =
32 (+ 8) chips
32k chips
64k chips
128k chips
256k chips
512k chips
1M chips
0
Figure 3 - RAM Store Subword sequence
IU drives byte store data
1
Chip org.
4 CS used =
16 (+ 4) chips
16k chips
32k chips
64k chips
128k chips
256k chips
512k chips
1M chips
2M chips
2
MEC loads whole word
Old checkbits
Chip org.
2 CS used =
8 (+ 2) chips
32k chips
64k chips
128k chips
256k chips
512k chips
1M chips
2M chips
4M chips
3
MEC drives new word
MEC drives new checkword
4
Chip org.
1 CS used =
4 (+ 1) chips
64k chips
128k chips
256k chips
512k chips
1M chips
2M chips
4M chips
8M chips
TSC693E
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