1. Overview
The program flow chart indicates the operation flow of the driver part for a E-paper display, including IC reset, IC initialization, display function, display update function, deep sleep function and so on. Commonly used SPI E-paper display ICs generally are Ultra-chip’s and Solomon tech’s . Of course, there are also a small amount of Fiti power’s, which can be classified as Ultrachip’s.

2. Operation steps
1) Solomon tech IC program flow chart:

2) Ultra-chip（Fiti Power）program flow chart：

3. Command comparison
The reset operation of these two ICs needs to pull down the IC reset pin for at least 10ms first, and then pull it up again; most of the E-paper displays have already built the data of the initialization into the IC, and only when using gray mode or rotation functions the additional commands are required; Solomon tech in the display function part is 0x24, 0x26 commands to be executed, while Ultra-chip 0x10, 0x13 commands to be executed; in the display update function, Solomon tech needs 0x22, (0xF7 full refresh, 0xC7 fast refresh, 0xFF partial refresh), 0x20, and the Ultra-chip only needs 0x12 command; the last is the deep sleep function, Solomon tech is 0x10, 0x01, and Ultra-chip is 0x02, 0x07, 0xA5. Generally, except for the reset, the other commands of these two ICs are different although they share a similar display operation process. In addition, Solomon tech IC has its own internal comparator, and only needs to execute the 0x24 command when performing monochrome display.