Intel 80L188EC 사용자 설명서
3-9
HARDWARE OVERVIEW
3
The Maxim MAX734 located at U11 is also a current-mode DC-DC converter. This device steps
up the V
up the V
CC
voltage to +12.0 volts. This voltage output is supplied to provide a V
PP
option for
Flash memory programming. The SHDN# input (pin 1) connects to a port pin (P1.1) on the
processor through an inverter. At reset, SHDN# is driven low to disable the +12 volt signal. The
output remains disabled until Port Pin 1.1 is programmed to a logic 0. When SHDN# is low, the
output (pin 8) is V
processor through an inverter. At reset, SHDN# is driven low to disable the +12 volt signal. The
output remains disabled until Port Pin 1.1 is programmed to a logic 0. When SHDN# is low, the
output (pin 8) is V
CC
minus a diode drop. The evaluation board uses SmartVoltage Flash. To
prevent unintentional writes to Flash, set jumpers E2 and E3 as indicated in Table 3-1.
3.6
SERIAL INTERFACE
Connector P1 connects to your PC’s serial port. P1 interfaces pin-to-pin with a standard nine-pin
RS-232 serial connector. Verify that the cable being used provides all signals required.
RS-232 serial connector. Verify that the cable being used provides all signals required.
Connector P2 is an additional serial port for user applications. Receive, Transmit, and Clear-to-
Send are connected. Other connector pins are routed to test points on the board.
Send are connected. Other connector pins are routed to test points on the board.
Table 3-3. P1 Host Serial Connector
P1 Connector
Pin
Nos.
Host RS-232
Signal Name
Connection on
Evaluation Board
1 (CF)
DCD Data Carrier Detect
DTR P1-pin 4
2 (BB)
RxD Receive Data
TxD of MAX561
3 (BA)
TxD Transmit Data
RxD of MAX561
4 (CD)
DTR Data Terminal Ready
INIT
5 (AB)
SG Signal Ground
Digital Ground
6 (CC)
DSR Data Set Ready
DTR P1-pin4
7 (CA)
RTS Request To Send
CTS P1-pin8
8 (CB)
CTS Clear To Send
RTS P1-pin7
9 (CE)
RI Ring Indicator
Run Indicator
1
2
3
4
5
6
7
8
9