PC912XDP512F0MPVR datasheet(1052/1348 Pages) FREESCALE

1052 / 1348 page

Chapter 25 2 Kbyte EEPROM Module (S12XEETX2KV1)

MC9S12XDP512 Data Sheet, Rev. 2.21

1054

Freescale Semiconductor

25.4.1.2

Command Write Sequence

The EEPROM command controller is used to supervise the command write sequence to execute program,

erase, erase verify, sector erase abort, and sector modify algorithms.

Before starting a command write sequence, the ACCERR and PVIOL ﬂags in the ESTAT register must be

clear (see Section 25.3.2.6, “EEPROM Status Register (ESTAT)”) and the CBEIF ﬂag should be tested to

determine the state of the address, data and command buffers. If the CBEIF ﬂag is set, indicating the

buffers are empty, a new command write sequence can be started. If the CBEIF ﬂag is clear, indicating the

buffers are not available, a new command write sequence will overwrite the contents of the address, data

and command buffers.

A command write sequence consists of three steps which must be strictly adhered to with writes to the

EEPROM module not permitted between the steps. However, EEPROM register and array reads are

allowed during a command write sequence. The basic command write sequence is as follows:

1. Write to one address in the EEPROM memory.

2. Write a valid command to the ECMD register.

3. Clear the CBEIF ﬂag in the ESTAT register by writing a 1 to CBEIF to launch the command.

The address written in step 1 will be stored in the EADDR registers and the data will be stored in the

EDATA registers. If the CBEIF ﬂag in the ESTAT register is clear when the ﬁrst EEPROM array write

occurs, the contents of the address and data buffers will be overwritten and the CBEIF ﬂag will be set.

When the CBEIF ﬂag is cleared, the CCIF ﬂag is cleared on the same bus cycle by the EEPROM command

controller indicating that the command was successfully launched. For all command write sequences

except sector erase abort, the CBEIF ﬂag will set four bus cycles after the CCIF ﬂag is cleared indicating

that the address, data, and command buffers are ready for a new command write sequence to begin. For

sector erase abort operations, the CBEIF ﬂag will remain clear until the operation completes. Except for

the sector erase abort command, a buffered command will wait for the active operation to be completed

before being launched. The sector erase abort command is launched when the CBEIF ﬂag is cleared as part

of a sector erase abort command write sequence. Once a command is launched, the completion of the

command operation is indicated by the setting of the CCIF ﬂag in the ESTAT register. The CCIF ﬂag will

set upon completion of all active and buffered commands.

25.4.2

EEPROM Commands

Table 25-9 summarizes the valid EEPROM commands along with the effects of the commands on the

EEPROM block.

Table 25-9. EEPROM Command Description

ECMDB

Command

Function on EEPROM Memory

0x05

Erase

Verify

Verify all memory bytes in the EEPROM block are erased. If the EEPROM block is erased, the

BLANK ﬂag in the ESTAT register will set upon command completion.

0x20

Program

Program a word (two bytes) in the EEPROM block.

0x40

Sector

Erase

Erase all four memory bytes in a sector of the EEPROM block.

PC912XDP512F0MPVR 데이터시트(PDF) 1052 Page - Freescale Semiconductor, Inc

PC912XDP512F0MPVR 데이터시트(HTML) 1052 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

데이터시트 다운로드

링크 URL