beautypg.com

Atmega162 boundary- scan order, Atmega162/v – Rainbow Electronics ATmega162V User Manual

Page 212

background image

212

ATmega162/V

2513E–AVR–09/03

ATmega162 Boundary-
scan Order

Table 88 shows the Scan order between TDI and TDO when the Boundary-scan chain
is selected as data path. Bit 0 is the LSB; the first bit scanned in, and the first bit
scanned out. The scan order follows the pinout order as far as possible. Therefore, the
bits of Port A and Port E is scanned in the opposite bit order of the other ports. Excep-
tions from the rules are the Scan chains for the analog circuits, which constitute the
most significant bits of the scan chain regardless of which physical pin they are con-
nected to. In Figure 87, PXn. Data corresponds to FF0, PXn. Control corresponds to
FF1, and PXn. Pullup_enable corresponds to FF2. Bit 4, 5, 6, and 7of Port C is not in the
scan chain, since these pins constitute the TAP pins when the JTAG is enabled.

Table 87. Boundary-scan Signals for the Analog Comparator

Signal
Name

Direction as
seen from the
Comparator

Description

Recommended
Input when Not
in Use

Output Values when
Recommended
Inputs are Used

AC_IDLE

input

Turns off Analog
comparator
when true

1

Depends upon µC
code being executed

ACO

output

Analog
Comparator
Output

Will become
input to µC code
being executed

0

ACBG

input

Bandgap
Reference
enable

0

Depends upon µC
code being executed

Table 88. ATmega162 Boundary-scan Order

Bit Number

Signal Name

Module

105

AC_IDLE

Comparator

104

ACO

103

ACBG

102

PB0.Data

Port B

101

PB0.Control

100

PB0.Pullup_Enable

99

PB1.Data

98

PB1.Control

97

PB1.Pullup_Enable

96

PB2.Data

95

PB2.Control

94

PB2.Pullup_Enable

93

PB3.Data

92

PB3.Control

91

PB3.Pullup_Enable

90

PB4.Data

89

PB4.Control

88

PB4.Pullup_Enable