AT89LP428 datasheet(95/149 Pages) ATMEL

95 / 149 page

3654A–MICRO–8/09

AT89LP428/828

17.3

Pin Configuration

When the SPI is enabled (SPE = 1), the data direction of the MOSI, MISO, SCK, and SS pins is

automatically overridden according to the MSTR bit as shown in Table 17-1. The user doesn’t

need to reconfigure the pins when switching from master to slave or vice-versa. For more details

on port configuration, refer to “Port Configuration” on page 35.

Notes:1. In these modes MOSI is active only during transfers. MOSI will be pulled high between transfers to allow other masters to

control the line.

2. In Push-pull mode MOSI is active only during transfers, otherwise it is tristated to prevent line contention. A weak external

pull-up may be required to prevent MOSI from floating.

Table 17-1.

SPI Pin Configuration and Behavior when SPE = 1

Mode

Master (MSTR = 1)

Slave (MSTR = 0)

SCK

Quasi-bidirectionalOutputInput (Internal Pull-up)

Push-pull OutputOutputInput (Tristate)

Input-only

No output (Tristated)

Input (Tristate)

Open-drain OutputOutput

Input (External Pull-up)

MOSI

Quasi-bidirectionalOutput(1)

Input (Internal Pull-up)

Push-pull OutputOutput(2)

Input (Tristate)

Input-only

No output (Tristated)

Input (Tristate)

Open-drain OutputOutput(1)

Input (External Pull-up)

MISO

Quasi-bidirectionalInput (Internal Pull-up)

Output (SS = 0)

Internal Pull-up (SS = 1 or DISSO = 1)

Push-pull OutputInput (Tristate)

Output (SS = 0)

Tristated (SS = 1 or DISSO = 1)

Input-only

Input (Tristate)

No output (Tristated)

Open-drain OutputInput (External Pull-up)

Output (SS = 0)

External Pull-up (SS = 1 or DISSO = 1)

AT89LP428 Arkusz danych(PDF) 95 Page - ATMEL Corporation

AT89LP428 Arkusz danych(HTML) 95 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

Arkusz danych Pobierz

Link URL