AT90S8515

Manufacturer Part NumberAT90S8515
Description8-bit microcontroller with 8K bytes in-system programmable flash, 2.7-6.0V
ManufacturerATMEL Corporation
AT90S8515 datasheet
 
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
Page 41
42
Page 42
43
Page 43
44
Page 44
45
Page 45
46
Page 46
47
Page 47
48
Page 48
49
Page 49
50
Page 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
101
102
103
104
105
106
107
108
109
110
111
112
Page 47/112:

Serial Peripheral Interface SPI

Download datasheet (3Mb)Embed
PrevNext
Serial Peripheral
Interface – SPI
0841G–09/01
The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer
between the AT90S8515 and peripheral devices or between several AVR devices. The
AT90S8515 SPI features include the following:
Full-duplex, 3-wire Synchronous Data Transfer
Master or Slave Operation
LSB First or MSB First Data Transfer
Four Programmable Bit Rates
End-of-Transmission Interrupt Flag
Write Collision Flag Protection
Wake-up from Idle Mode (Slave Mode Only)
Figure 34. SPI Block Diagram
The interconnection between master and slave CPUs with SPI is shown in Figure 35.
The PB7(SCK) pin is the clock output in the Master Mode and is the clock input in the
Slave Mode. Writing to the SPI Data Register of the master CPU starts the SPI clock
generator and the data written shifts out of the PB5(MOSI) pin and into the PB5(MOSI)
pin of the slave CPU. After shifting one byte, the SPI clock generator stops, setting the
end-of-transmission flag (SPIF). If the SPI interrupt enable bit (SPIE) in the SPCR regis-
ter is set, an interrupt is requested. The Slave Select input, PB4(SS), is set low to select
an individual slave SPI device. The two shift registers in the master and the slave can be
considered as one distributed 16-bit circular shift register. This is shown in Figure 35.
When data is shifted from the master to the slave, data is also shifted in the opposite
direction, simultaneously. This means that during one shift cycle, data in the master and
the slave are interchanged.
AT90S8515
47