AT90USB646 datasheet(381/459 Pages) ATMEL

381 / 459 page

381

7593H–AVR–11/08

ATmega32U6/AT90USB64/128

29.8

Serial Programming Pin Mapping

Figure 29-10. Serial Programming and Verify(1)

Notes:

1. If the device is clocked by the internal Oscillator, it is no need to connect a clock source to the

XTAL1 pin.

2. V

CC - 0.3V < AVCC < VCC + 0.3V, however, AVCC should always be within 1.8 - 5.5V

When programming the EEPROM, an auto-erase cycle is built into the self-timed programming

operation (in the Serial mode ONLY) and there is no need to first execute the Chip Erase

instruction. The Chip Erase operation turns the content of every memory location in both the

Program and EEPROM arrays into 0xFF.

Depending on CKSEL Fuses, a valid clock must be present. The minimum low and high periods

for the serial clock (SCK) input are defined as follows:

Low: > 2 CPU clock cycles for f

ck < 12 MHz, 3 CPU clock cycles for fck >= 12 MHz

High: > 2 CPU clock cycles for fck < 12 MHz, 3 CPU clock cycles for fck >= 12 MHz

29.8.1

Serial Programming Algorithm

When writing serial data to the ATmega32U6/AT90USB64/128, data is clocked on the rising

edge of SCK.

When reading data from the ATmega32U6/AT90USB64/128, data is clocked on the falling edge

of SCK. See Figure 29-11 for timing details.

To program and verify the ATmega32U6/AT90USB64/128 in the serial programming mode, the

following sequence is recommended (See four byte instruction formats in Table 29-16):

Table 29-14. Pin Mapping Serial Programming

Symbol

Pins

(TQFP-64)

I/O

Description

PDI

PB2

Serial Data in

PDO

PB3

Serial Data out

SCK

PB1

Serial Clock

VCC

GND

XTAL1

SCK

PDO

PDI

RESET

+1.8 - 5.5V

AVCC

+1.8 - 5.5V

(2)

AT90USB646 Datasheet(PDF) 381 Page - ATMEL Corporation

AT90USB646 Datasheet(HTML) 381 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL