The Flash is organized in pages. When
programming the Flash, the program data is latched into a page buffer. This allows one
page of program data to be programmed simultaneously. The following procedure describes
how to program the entire Flash memory:
Step A. Load Command “Write
Flash”.
- 1.Set XA1, XA0 to “10”. This
enables command loading.
- 2.Set BS1 to “0”.
- 3.Set DATA to “0001 0000”. This is
the command for Write Flash.
- 4.Give XTAL1 a positive pulse.
This loads the command.
Step B. Load Address Low
Byte.
- 1.Set XA1, XA0 to “00”. This
enables address loading.
- 2.Set BS1 to “0”. This selects low
address.
- 3.Set DATA = Address low byte
(0x00 - 0xFF).
- 4.Give XTAL1 a positive pulse.
This loads the address low byte.
Step C. Load Data Low
Byte.
- 1.Set XA1, XA0 to “01”. This
enables data loading.
- 2.Set DATA = Data low byte (0x00 -
0xFF).
- 3.Give XTAL1 a positive pulse.
This loads the data byte.
Step D. Load Data High
Byte.
- 1.Set BS1 to “1”. This selects
high data byte.
- 2.Set XA1, XA0 to “01”. This
enables data loading.
- 3.Set DATA = Data high byte (0x00
- 0xFF).
- 4.Give XTAL1 a positive pulse.
This loads the data byte.
Step E. Latch Data.
- 1.Set BS1 to “1”. This selects
high data byte.
- 2.Give PAGEL a positive pulse.
This latches the data bytes. (Refer to figure Programming the Flash Waveforms in this
section for signal waveforms)
Step F. Repeat B through E until
the entire buffer is filled or until all data within the page is loaded.
While the lower bits in the address
are mapped to words within the page, the higher bits address the pages within the
FLASH. This is illustrated in the following figure, Addressing the Flash Which is Organized in Pages, in this
section. Note that if less than eight bits are required to address words in the page
(pagesize < 256), the most significant bit(s) in the address low byte are used to
address the page when performing a Page Write.
Step G. Load Address High
byte.
- 1.Set XA1, XA0 to “00”. This
enables address loading.
- 2.Set BS1 to “1”. This selects
high address.
- 3.Set DATA = Address high byte
(0x00 - 0xFF).
- 4.Give XTAL1 a positive pulse.
This loads the address high byte.
Step H. Program Page.
- 1.Set BS1 = “0”
- 2.Give WR
a negative pulse. This starts programming of the entire page of data.
RDY/BSY goes low.
- 3.Wait until
RDY/BSY goes high (Refer to figure Programming the Flash Waveforms in this section).
Step I. Repeat B through H until
the entire Flash is programmed or until all data has been programmed.
Step J. End Page
Programming.
- 1.1. Set XA1, XA0 to “10”. This
enables command loading.
- 2.Set DATA to “0000 0000”. This is
the command for No Operation.
- 3.Give XTAL1 a positive pulse.
This loads the command, and the internal write signals are reset.
Figure 1. Addressing the Flash Which is
Organized in Pages
Note: PCPAGE and PCWORD are listed in
the section Page Size.
Figure 2. Programming the Flash
Waveform
Note: “XX” is don’t care. The letters
refer to the programming description above.