Freescale Semiconductor 56F8122 User Manual
Page 90
56F8322 Techncial Data, Rev. 10.0
90
Freescale Semiconductor
Preliminary
Figure 6-13 I/O Short Address Determination
With this register set, an interrupt driver can set the SIM_ISALL 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:
The default value of this register set points to the EOnCE registers.
Note:
The pipeline delay between setting this register set and using short I/O addressing with the new value
is five cycles.
Figure 6-14 I/O Short Address Location High Register (SIM_ISALH)
6.5.10.1 Input/Output Short Address Low (ISAL[23:22])—Bit 1–0
This field represents the upper two address bits of the “hard coded” I/O short address.
Figure 6-15 I/O Short Address Location Low Register (SIM_ISALL)
Base + $D
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Read
1
1
1
1
1
1
1
1
1
1
1
1
1
1
ISAL[23:22]
Write
RESET
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Base + $E
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Read
ISAL[21:6]
Write
RESET
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Instruction Portion
“
Hard Coded” Address Portion
6 Bits from I/O Short Address Mode Instruction
16 Bits from SIM_ISALL Register
2 bits from SIM_ISALH Register
Full 24-Bit for Short I/O Address