Cypress PSoC CY8C23533, Technical Reference Manual

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48 Document # 001-20559 Rev. *D
Supervisory ROM (SROM)
3.1.2.3 WriteBlock Function
The WriteBlock function is used to store data in the Flash.
Data is moved 64 bytes at a time from SRAM to Flash using
this function. Before a write can be performed, either an
EraseAll or an EraseBlock must be completed successfully.
The first thing the WriteBlock function does is check the pro-
tection bits and determine if the desired BLOCKID is write-
able. If write protection is turned on, the WriteBlock function
exits, setting the accumulator and KEY2 back to 00h. KEY1
has a value of 01h, indicating a write failure. Write protection
is set when the PSoC device is programmed externally and
cannot be changed through the SSC function.
The BLOCKID of the Flash block , where the data is stored,
must be determined and stored at SRAM address FAh. For
valid BLOCKID values, refer to
Table 3-5 .
An MVI A, [expr] instruction is used to move data from
SRAM into Flash. Therefore, the MVI read pointer (MVR_PP
register) can be used to specify which SRAM page data is
pulled from. Using the MVI read pointer and the parameter
blocks POINTER value allows the SROM WriteBlock func-
tion to move data from any SRAM page into any Flash
block, in either Flash bank.
The SRAM address, of the first of the 64 bytes to be stored
in Flash, must be indicated using the POINTER variable in
the parameter block (SRAM address FBh).
Finally, the CLOCK and DELAY value must be set correctly.
The CLOCK value determines the length of the write
pulse
that is used to store the data in the Flash. The CLOCK and
DELAY values are dependent on the CPU speed and must
be set correctly. Refer to
“Clocking” on page 53 for addi-
tional information.
If the PSoC device you are using has more than one bank of
Flash, the bank value in the FLS_PR1 register must be set
prior to executing the SSC instruction. Refer to
Table 3-5 .
3.1.2.4 EraseBlock Function
The EraseBlock function is used to erase a block of 64 con-
tiguous bytes in Flash.
The first thing the EraseBlock function does is check the
protection bits and determine if the desired BLOCKID is
writeable. If write protection is turned on, the EraseBlock
function exits, setting the accumulator and KEY2 back to
00h. KEY1 has a value of 01h, indicating a write failure.
To set up the parameter block for the EraseBlock function,
correct key values must be stored in KEY1 and KEY2. The
block number to be erased must be stored in the BLOCKID
variable, and the CLOCK and DELAY values must be set
based on the current CPU speed. For more information on
setting the CLOCK and DELAY values,
see “Clocking” on
page 53 .
If the PSoC device you are using has more than one bank of
Flash, the bank value in the FLS_PR1 register must be set
prior to executing the SSC instruction. Refer to
Table 3-5 .
Table 3-7. WriteBlock Parameters (02h)
Name Address Type Description
MVR_PP 0,D4h Register MVI read page pointer register.
KEY1 0,F8h RAM 3Ah.
KEY2 0,F9h RAM Stack Pointer value+3, when SSC is
executed.
BLOCKID 0,FAh RAM Flash block number.
POINTER 0,FBh RAM First of 64 addresses in SRAM, where
the data to be stored in Flash is located
prior to calling WriteBlock.
CLOCK 0,FCh RAM Clock divider used to set the write pulse
width.
DELAY 0,FEh RAM For a CPU speed of 12 MHz, set to 56h.
FLS_PR1 1,FAh Register Flash bank number.
Table 3-8. EraseBlock Parameters (03h)
Name Address Type Description
KEY1 0,F8h RAM 3Ah
KEY2 0,F9h RAM Stack Pointer value+3, when SSC is
executed.
BLOCKID 0,FAh RAM Flash block number.
CLOCK 0,FCh RAM Clock divider used to set the erase
pulse width.
DELAY 0,FEh RAM For a CPU speed of 12 MHz, set to
56h.
FLS_PR1 1,FAh Register Flash bank number.