IA186EM_11 Datasheet, PDF (70/146 Pages) InnovASIC, Inc – 8-Bit/16-Bit Microcontrollers

IA186EM/IA188EM
8-Bit/16-Bit Microcontrollers
Data Sheet
February 25, 2011
pcs3_n–pcs0_n Wait-State Encoding
R3 R1 R0 Wait States
000
0
001
1
010
2
011
3
100
5
101
7
110
9
111
15
Bit [2]—R2 → Ready Mode. When set to 1, external ready is ignored. When 0, it is
required. In each case the number of wait states is determined according to the
pcs3_n–pcs0_n Wait-State Encoding shown above.
Bits [1–0]—R1–R0 → Wait-State Value (see pcs3_n–pcs0_n Wait-State Encoding
above). The pcs6_n–pcs5_n and pcs3_n–pcs0_n pins are multiplexed with the PIO pins.
For these to function as chip selects, the PIO mode and direction settings for these pins
must be set to 0 for normal operation.
5.1.17 LMCS (0a2h)
The Low-Memory Chip Select (LMCS) Register configures the LMCS provided to facilitate
access to the interrupt vector table located at 00000h or the bottom of memory. The lcs_n pin is
not active at reset.
The width of the data bus for the lcs_n space should be configured in the AUXCON register
before activating the lcs_n chip select pin, by any write access to the LMCS register. The value
of the LMCS register is undefined at reset except DA, which is set to 0 (see Table 33).
Table 33. Low-Memory Chip Select Register
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Res UB2–UB0
Reserved DA PSE Reserved R2 R1–R0
Bit [15]—Reserved → Set to 0.
Bits [14–12]—UB2–UB0 → Upper Boundary. These bits define the upper boundary of
memory accessed by the lcs_n chip select. The list below presents the possible block-size
configurations (a 512-Kbyte maximum).
®
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