Section 26
Boundary Scan (JTAG)
Rev. 1.00 Mar. 12, 2008 Page 1047 of 1178
REJ09B0403-0100
26.6 Usage
Notes
1. A reset must always be executed by driving the
ETRST
pin to 0, regardless of whether or not
the JTAG is to be activated. The
ETRST
pin must be held low for 20 ETCK clock cycles. For
details, see section 31, Electrical Characteristics. To activate the JTAG after a reset, drive the
ETRST
pin to 1 and specify the ETCK, ETMS, and ETDI pins to any value. If the JTAG is not
to be activated, drive the
ETRST
, ETCK, ETMS, and ETDI pins to 1 or the high-impedance
state. These pins are internally pulled up and are noted in standby mode.
2. The following must be considered when the power-on reset signal is applied to the
ETRST
pin.
The reset signal must be applied at power-on.
To prevent the LSI system operation from being affected by the
ETRST
pin of the board
tester, circuits must be separated .
Alternatively, to prevent the
ETRST
pin of the board tester from being affected by the LSI
system reset, circuits must be separated.
Figure 26.3 shows a design example of the reset signal circuit wherein no reset signal
interference occurs.
Power-on
reset circuit
Board edge pin
System reset
ETRST
RES
ETRST
This LSI
Figure 26.3 Reset Signal Circuit Without Reset Signal Interference
Summary of Contents for H8S Family
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Page 70: ...Section 1 Overview Rev 1 00 Mar 12 2008 Page 22 of 1178 REJ09B0403 0100...
Page 108: ...Section 2 CPU Rev 1 00 Mar 12 2008 Page 60 of 1178 REJ09B0403 0100...
Page 116: ...Section 3 MCU Operating Modes Rev 1 00 Mar 12 2008 Page 68 of 1178 REJ09B0403 0100...
Page 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Page 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Page 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Page 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Page 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Page 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Page 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Page 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Page 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Page 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Page 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
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