Boot ROM Pin description

When the ISP entry pin is pulled LOW on reset, the part enters ISP mode and the ISP command handler starts up. In ISP mode, pin PIO0_0 is connected to function U0_RXD and pin PIO0_4 is connected to function U0_TXD on the USART0 block.

Table 1. Boot ROM Pin location in ISP mode
ISP entry pin USART RXD USART TXD Marking Boot loader version Package
PIO0_1 PIO0_0 PIO0_4 1A v 13.1 TSSOP20; SO20; TSSOP16; DIP8; XSON16
PIO0_1 PIO0_0 PIO0_4 2A v 13.2 TSSOP20; SO20; TSSOP16; DIP8; XSON16
PIO0_1 PIO0_0 PIO0_4 4C and later v 13.4 and later DIP8
PIO0_12 PIO0_0 PIO0_4 4C and later v 13.4 and later TSSOP20; SO20; XSON16; TSSOP16

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