mc56f801 Freescale Semiconductor, Inc, mc56f801 Datasheet - Page 75

• Manufacturer Part Number: mc56f801
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

With this register set, an interrupt driver can set the SIM_IOSALO register pair to point to its peripheral
registers and then use the I/O Short addressing mode to reference them. The ISR should restore this register
to its previous contents prior to returning from interrupt.
Note:
Note:
6.3.10.1
This bit field is reserved or not implemented. It is read as 0 and cannot be modified by writing.
6.3.10.2
This field represents the upper two address bits of the “hard coded” I/O short address.
Freescale Semiconductor
Preliminary
Base + $D
RESET
Write
Read
The default value of this register set points to the EOnCE registers.
The pipeline delay between setting this register set and using short I/O addressing with the new value
is five instruction cycles.
Figure 6-13 I/O Short Address Location High Register (SIM_IOSAHI)
Reserved—Bits 15—2
Input/Output Short Address Location (ISAL[23:22])—Bit 1–0
2 bits from SIM_IOSAHI Register
15
Full 24-Bit for Short I/O Address
0
0
16 Bits from SIM_IOSALO Register
14
0
0
Figure 6-12 I/O Short Address Determination
13
0
0
6 Bits from I/O Short Address Mode Instruction
12
0
0
11
56F8014 Technical Data, Rev. 9
0
0
10
0
0
“
Hard Coded” Address Portion
9
0
0
8
0
0
7
0
0
6
0
0
5
0
0
Instruction Portion
4
0
0
3
0
0
2
0
0
Register Descriptions
ISAL[23:22]
1
1
0
1
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