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| Low-speed |  |  |  |  |  |  | ||||
| S/N | Operation Voltage | ROM Size(B) | RAM Size(B) | GPIOs | External Interrupts | 8-bit Timer | Built-in Regulator | Endpoints | USB Interfact | Package Type | 
| 1 | 4.35~5.5V | 8K (MTP) | 256 | 34 | 2 | 1 | 3.3V | 4 | USB & PS/2 Combo | DICE,DIP40,SSOP28 | 
| 2 | 4.35~5.5V | 8K (Mask) | 256 | 34 | 2 | 1 | 3.3V | 4 | USB & PS/2 Combo | DICE,DIP40,SSOP28 |