PROGRAMMER
′′
S MODEL
S3C2501X
2-26
Each register contains the access permission bits, apn[1:0], for the eight areas of instruction or data memory, as
shown in Table 2-12.
All defined bits in the protection registers are set to zero at reset.
Table 2-12. Protection Space Register Format
Register Bits
Functions
15:14
ap7[1:0] bits of area 7
13:12
ap6[1:0] bits of area 6
11:10
ap5[1:0] bits of area 5
9:8
ap4[1:0] bits of area 4
7:6
ap3[1:0] bits of area 3
5:4
ap2[1:0] bits of area 2
3:2
ap1[1:0] bits of area 1
1:0
ap0[1:0] bits of area 0
The values of the Iapn[1:0] and Dapn[1:0] bits define the access permission for each area of memory.
The encoding is shown in Table 2-13.
NOTE
On reset, the values of the Iapn[1:0] and Dapn[1:0] bits for all areas are undefined. However, as on reset,
the protection unit is disabled and all areas are effectively set to no access. The protection space
registers therefore, must be programmed before the protection unit is enabled.
Table 2-13. Permission Encoding
I/Dapn[1:0]
Permission
00
No access.
01
Privileged mode access only.
10
Privileged mode full access, user mode read only.
11
Full access.
Summary of Contents for S3C2501X
Page 18: ......
Page 275: ...MEMORY CONTROLLER S3C2501X 5 60 NOTES ...
Page 289: ...I2C CONTROLLER S3C2501X 6 14 NOTES ...
Page 373: ...GDMA CONTROLLER S3C2501X 9 24 NOTES ...
Page 435: ...I O PORTS S3C2501X 12 12 NOTES ...