IA186EM_04 Datasheet, PDF (16/133 Pages) InnovASIC, Inc – 8/16-Bit Microcontrollers

IA186EM/IA188EM
8/16-BIT Microcontrollers
Data Sheet
As of Production Version -03
DSA [15:0] (bits 15-0) – DMA Source Address Low bits are placed onto a15-a0 during the read phase
of a DMA transfer.
MPCS (0a8h) - MCS and PCS Auxiliary Register.
This register controls more than one type of chip select, making it different from the other chip select
control registers. The MPCS register contains information for the following, mcs3_n - mcs0_n as well as
pcs6_n - pcs5_n and pcs3_n - pcs0_n.
The MPCS register also contains a bit that configures the pcs6_n - pcs5_n pins as either chip selects or as
alternate sources for the A2 and A1 address bits. Either address bits a1 & a2 or pcs6_n - pcs5_n are
selected to the exclusion of the other. When programmed for address bits, these outputs can be used to
provide latched address bits for a2 & a1
pcs6_n - pcs5_n are high and not active on processor reset. An access to the MPCS register causes the
pins to activate, when the pcs6_n - pcs5_n are configured as address pins. The pcs6_n - pcs5_n pins do
not require corresponding access to the PACS register to be activated.
The value of the MPCS register is undefined at reset.
15 14
13 12 11 10 9 8 7 6 5 4 3 2 1 0
1
M6-M0
EX MS 1 1 1 R2 R1-R0
Reserved (bit 15) – Set to 1.
M [6:0] (bits14-8) MCS_n Block Size – These seven bits determine the total block size for the
MCS3_n - MCS0_n chip selects. The total block size is divided equally among the four chip selects.
The following table shows the relationship between M [6:0] and the size of the memory block.
Total Block
Size
8K
16K
32K
64K
128K
256K
512K
Individual
Select Size
2K
4K
8K
16K
32K
64K
128K
M6 – M0
0000001b
0000010b
0000100b
0001000b
0010000b
0100000b
1000000b
EX (bit7) Pin Selector – This bit determines whether the pcs6_n - pcs5_n pins are configured as chip
selects or as alternate outputs for a2 & a1. When this bit is set to 1, pcs6_n - pcs5_n are configured
as peripheral chip select pins, whereas when set to 0, pcs6_n - pcs5_n become address bit a1 and
address bit a2 respectively.
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