20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 70

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

60
Bit(s)
7:0
Write-Protect x Register
Value
0
1
Disable write protection for the corresponding 64K segment.
Enable write protection for the corresponding 64K block.
The 8 MSBs of the 24-bit physical address of any specific 64K block can be used
to determine which write-protect register to use.
Since there are 256 64K blocks in the 16MB memory space, the 8 MSBs (the
memory block must be on a 64K boundary) of the physical address is divided by
256. In total there are 32 write-protect registers, so the result is further divided by
32. This number is then added to the address of the first write-protect register
(0x460) to give the address of the write-protect register that controls the 64K
block in question.
Each write-protect register controls 8 64K blocks. Now that you have the register
address, you need to know that the register bit selects the correct 64K block. This
is calculated using blk64, a value between 0–255.
physaddr = xxxxxxh
blk64 = physaddr 16
regnum = blk64 3
register address = regnum + 0x460
bitnum = blk64 & 0x7
(WP10R)
(WP11R)
(WP12R)
(WP13R)
(WP14R)
(WP15R)
(WP16R)
(WP17R)
(WP18R)
(WP19R)
(WP20R)
(WP21R)
(WP22R)
(WP23R)
(WP24R)
(WP25R)
(WP26R)
(WP27R)
(WP28R)
(WP29R)
(WP30R)
(WP31R)
(WP0R)
(WP1R)
(WP2R)
(WP3R)
(WP4R)
(WP5R)
(WP6R)
(WP7R)
(WP8R)
(WP9R)
Description
Rabbit 4000 Microprocessor User’s Manual
(Address = 0x046A)
(Address = 0x046B)
(Address = 0x046C)
(Address = 0x046D)
(Address = 0x047A)
(Address = 0x047B)
(Address = 0x047C)
(Address = 0x047D)
(Address = 0x046E)
(Address = 0x046F)
(Address = 0x047E)
(Address = 0x047F)
(Address = 0x0460)
(Address = 0x0461)
(Address = 0x0462)
(Address = 0x0463)
(Address = 0x0464)
(Address = 0x0465)
(Address = 0x0466)
(Address = 0x0467)
(Address = 0x0468)
(Address = 0x0469)
(Address = 0x0470)
(Address = 0x0471)
(Address = 0x0472)
(Address = 0x0473)
(Address = 0x0474)
(Address = 0x0475)
(Address = 0x0476)
(Address = 0x0477)
(Address = 0x0478)
(Address = 0x0479)