IAP example with SPI

AN2737

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2.3.3

Write command

The write command allows data in the Flash program memory of the STM8 to be written,

starting from any Flash addressing range.

The packet sequence to achieve a ‘write’ with the Aardvark software and STM8 SPI is

explained below and is summarized in Figure 13 and Figure 14.

As per Section 2.3.2: Read command on page 12, select the master tabsheet, set the

bitrate (for write operations up to 8 MHz can be chosen), select the rising/falling polarity and

the sample/setup phase, and set the active low option for the SS pin.

Two steps are then required to carry out a write command.

Step 1: In the ‘message window’ text box enter the OPC-WREN value (06h) and press

‘send’. This byte is used to activate the write mode.

Step 2: In the ‘message window’ text box enter OPC-WRT ADD DATA-W and press ‘send’.

For example, 02 01 90 FF AA 55 BB 66 programs 4 bytes starting from address 0190FFh.

Figure 13.

Step 1 of the write packet sequence using Aardvark software

Figure 14.

Step 2 of the write packet sequence using Aardvark software

In step 2, a maximun of 128 bytes can be programmed. When step 2 is finished, the NSS

signal rises up and the Flash is programmed with the DATA-W bytes at the ADD address.

At the end of this command, the data are written in the Flash memory. They can be verified

using the STVD memory window or by performing an SPI read.

OPC-WREN

00h

MOSI line

MISO line

OPC-WRT

ADD

DATA-W

00h

00h

0x00 (1 byte per byte programmed)

MOSI line

MISO line