Cypress PSoC CY8CTMG20 Series, Technical Reference Manual

Page: 36 / 308

36 PSoC CY8CTMG20x and CY8CTST200 TRM, Document No. 001-53603 Rev. *C
Supervisory ROM (SROM)
An
MVI A, [expr]
instruction is used to move data from
SRAM into Flash. Therefore, use the
MVI
read pointer
(MVR_PP register) to specify which SRAM page from which
data is pulled. 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.
The SRAM address, the first of the 128 bytes to store in
Flash, is indicated using the POINTER variable in the
parameter block (SRAM address FBh).
3.1.2.4 EraseBlock Function
The EraseBlock function is not recommended for use. The
functionality is redundant with the WriteBlock and WriteAnd-
Verify functions. The only practical use is for clearing all data
in a 128 byte block of contiguous bytes in Flash to 0x00. If
used, it should not be called repeatedly on the same block. It
may be used between WriteAndVerify or WriteBlock opera-
tions.
If write protection is turned on, then 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,
store the correct key values in KEY1 and KEY2. The block
number to erase must be stored in the BLOCKID variable.
3.1.2.5 ProtectBlock Function
The PSoC devices offer Flash protection on a block-by-
block basis.
Table 3-10 lists the protection modes available.
In the table, ER and EW indicate the ability to perform exter-
nal reads and writes (that is, by an external programmer).
For internal writes, IW is used. Internal reading is always
permitted by way of the
ROMX
instruction. An SR indicates
the ability to read by way of the SROM ReadBlock function.
In this table, note that all protection is removed by EraseAll.
3.1.2.6 TableRead Function
The TableRead function gives the user access to part-spe-
cific data stored in the Flash during manufacturing. The
Flash for these tables is separate from the program Flash
and is not directly accessible. It also returns a revision ID for
the die (do not confuse this with the silicon ID stored in the
Table 0 row in
Table 3-14 ).
There are four 8-byte tables in the CY8CTMG20x,
CY8CTST200 devices.
3.1.2.7 EraseAll Function
The EraseAll function performs a series of steps that
destroys the user data in the Flash banks and resets the
protection block in each Flash bank to all zeros (the unpro-
tected state). This function is only executed by an external
programmer. If EraseAll is executed from code, the M8C
HALTs without touching the Flash or protections. See
Table
3-13 . The three other hidden blocks above the protection
block, in each Flash bank, are not affected by the EraseAll.
Table 3-8. 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 128 addresses in SRAM, where
the data to be stored in Flash, is located
before calling WriteBlock.
Table 3-9. 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.
Table 3-10. Protect Block Modes
Mode Settings Description In PSoC Designer
00b SR ER EW IW Unprotected U = Unprotected
01b SR ER EW IW Read protect F = Factory upgrade
10b SR ER EW IW Disable external write R = Field upgrade
11b SR ER EW IW Disable internal write W = Full protection
Table 3-11. Protection Level Bit Packing
7 6 5 4 3 2 1 0
Block n+3 Block n+2 Block n+1 Block n
Table 3-12. TableRead Parameters (06h)
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 Table number to read.
Table 3-13. EraseAll Parameters (05h)
Name Address Type Description
KEY1 0,F8h RAM 3Ah.
KEY2 0,F9h RAM
Stack Pointer value+3, when
SSC
is
executed.
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