Cypress CY7C638xx, CY7C63310 manual ProtectBlock Parameters Name Address Description

CY7C63310, CY7C638xx

Table 9-8. ProtectBlock Parameters

Name	Address	Description
KEY1	0,F8h	3Ah
KEY2	0,F9h	Stack Pointer value when SSC is
		executed.
CLOCK	0,FCh	Clock divider used to set the write pulse
		width.
DELAY	0,FEh	For a CPU speed of 12 MHz set to 56h.

9.5.6 EraseAll Function

The EraseAll function performs a series of steps that destroy the user data in the Flash macros and resets the protection block in each Flash macro to all zeros (the unprotected state). The EraseAll function does not affect the three hidden blocks above the protection block, in each Flash macro. The first of these four hidden blocks is used to store the protection table for its eight Kbytes of user data.

The EraseAll function begins by erasing the user space of the Flash macro with the highest address range. A bulk program of all zeros is then performed on the same Flash macro, to destroy all traces of the previous contents. The bulk program is followed by a second erase that leaves the Flash macro in a state ready for writing. The erase, program, erase sequence is then performed on the next lowest Flash macro in the address space if it exists. After the erase of the user space, the protection block for the Flash macro with the highest address range is erased. Following the erase of the protection block, zeros are written into every bit of the protection table. The next lowest Flash macro in the address space then has its protection block erased and filled with zeros.

The end result of the EraseAll function is that all user data in the Flash is destroyed and the Flash is left in an unprogrammed state, ready to accept one of the various write commands. The protection bits for all user data are also reset to the zero state

The parameter block values that must be set, besides the keys, are the CLOCK and DELAY values.

Table 9-9. EraseAll Parameters

Name	Address	Description
KEY1	0,F8h	3Ah
KEY2	0,F9h	Stack Pointer value when SSC is
		executed.
CLOCK	0,FCh	Clock divider used to set the write pulse
		width.
DELAY	0,FEh	For a CPU speed of 12 MHz set to 56h

9.5.7 TableRead Function

The TableRead function gives the user access to part specific data stored in the Flash during manufacturing. It also returns a Revision ID for the die (not to be confused with the Silicon ID).

Table 9-10. Table Read Parameters

Name	Address	Description
KEY1	0,F8h	3Ah
KEY2	0,F9h	Stack Pointer value when SSC is
		executed.
BLOCKID	0,FAh	Table number to read.

The table space for the enCoRe II is simply a 64 byte row broken up into eight tables of eight bytes. The tables are numbered zero through seven. All user and hidden blocks in the CY7C638xx parts consist of 64 bytes.

An internal table (Table 0) holds the Silicon ID and returns the Revision ID. The Silicon ID is returned in SRAM, while the Revision and Family IDs are returned in the CPU_A and CPU_X registers. The Silicon ID is a value placed in the table by programming the Flash and is controlled by Cypress Semicon- ductor Product Engineering. The Revision ID is hard coded into the SROM and also redundantly placed in SROM Table 1. This is discussed in more detail later in this section.

SROM Table 1 holds Family/Die ID and Revision ID values for the device and returns a one-byte internal revision counter. The internal revision counter starts out with a value of zero and is incremented when one of the other revision numbers is not incre- mented. It is reset to zero when one of the other revision numbers is incremented. The internal revision count is returned in the CPU_A register. The CPU_X register is always set to FFh when Table 1 is read. The CPU_A and CPU_X registers always return a value of FFh when Tables 2-7 are read. The BLOCKID value, in the parameter block, indicates which table must be returned to the user. Only the three least significant bits of the BLOCKID parameter are used by TableRead function for enCoRe II devices. The upper five bits are ignored. When the function is called, it transfers bytes from the table to SRAM addresses F8h–FFh.

The M8C’s A and X registers are used by the TableRead function to return the die’s Revision ID. The Revision ID is a 16-bit value hard coded into the SROM that uniquely identifies the die’s design.

The return values for corresponding Table calls are tabulated as shown in Table 9-11on page 17

Table 9-11. Return values for Table Read

Table Number		Return Value
	A		X
0	Revision ID		Family ID
1	Internal Revision Counter		0xFF
2-7	0xFF		0xFF

Document 38-08035 Rev. *K Page 17 of 83

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