參數(shù)資料
型號: 12CE673
廠商: Microchip Technology Inc.
英文描述: HookUp/Lead Wire; Conductor Size AWG:18; No. Strands x Strand Size:65 x 36; Jacket Color:Black; Conductor Material:Copper; Jacket Material:Rubber; Leaded Process Compatible:Yes; Number of Conductors:1; Outer Diameter:0.144" RoHS Compliant: Yes
中文描述: 8引腳,8位CMOS微控制器與A / D轉(zhuǎn)換器和EEPROM數(shù)據(jù)存儲器
文件頁數(shù): 29/116頁
文件大?。?/td> 671K
代理商: 12CE673
1998 Microchip Technology Inc.
Preliminary
DS40181B-page 29
PIC12CE67X
6.3
WRITE OPERATIONS
6.3.1
BYTE WRITE
Following the start signal from the processor, the
device code (4 bits), the don't care bits (3 bits), and the
R/W bit (which is a logic low) are placed onto the bus
by the processor. This indicates to the addressed
EEPROM that a byte with a word address will follow
after it has generated an acknowledge bit during the
ninth clock cycle. Therefore, the next byte transmitted
by the processor is the word address and will be written
into the address pointer. Only the lower four address
bits are used by the device, and the upper four bits are
don’t cares. The address byte is acknowledgeable and
the processor will then transmit the data word to be
written into the addressed memory location. The mem-
ory acknowledges again and the processor generates
a stop condition. This initiates the internal write cycle,
and during this time will not generate acknowledge sig-
nals (Figure 6-5). After a byte write command, the inter-
nal address counter will not be incremented and will
point to the same address location that was just written.
If a stop bit is transmitted to the device at any point in
the write command sequence before the entire
sequence is complete, then the command will abort
and no data will be written. If more than 8 data bits are
transmitted before the stop bit is sent, then the device
will clear the previously loaded byte and begin loading
the data buffer again. If more than one data byte is
transmitted to the device and a stop bit is sent before a
full eight data bits have been transmitted, then the write
command will abort and no data will be written. The
EEPROM memory employs a V
CC
threshold detector
circuit which disables the internal erase/write logic if the
V
CC
is below minimum VDD. Byte write operations
must be preceded and immediately followed by a bus
not busy bus cycle where both SDA and SCL are held
high.
6.4
ACKNOWLEDGE POLLING
Since the EEPROM will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the stop condition for a write com-
mand has been issued from the processor, the device
initiates the internally timed write cycle. ACK polling
can be initiated immediately. This involves the proces-
sor sending a start condition followed by the control
byte for a write command (R/W = 0). If the device is still
busy with the write cycle, then no ACK will be returned.
If no ACK is returned, then the start bit and control byte
must be re-sent. If the cycle is complete, then the
device will return the ACK and the processor can then
proceed with the next read or write command. See
Figure 6-4 for flow diagram.
FIGURE 6-4:
ACKNOWLEDGE POLLING
FLOW
Send
Write Command
Send Stop
Condition to
Initiate Write Cycle
Send Start
Send Control Byte
with R/W = 0
Did EEPROM
Acknowledge
(ACK = 0)
Next
Operation
NO
YES
FIGURE 6-5:
BYTE WRITE
S
P
BUS ACTIVITY
PROCESSOR
SDA LINE
BUS ACTIVITY
S
T
A
R
T
S
T
O
P
CONTROL
BYTE
WORD
ADDRESS
DATA
A
C
K
A
C
K
A
C
K
1
0
X
1
0
X
X
X
X = Don’t Care Bit
X
X
X
0
相關(guān)PDF資料
PDF描述
12CGQ150 SCHOTTKY RECTIFIER
12CTQ030 12 AMP DUAL SCHOTTKY CENTER TAP RECTIFIERS
12CTQ SCHOTTKY RECTIFIER
12CTQ035-1 SCHOTTKY RECTIFIER
12CTQ035S SCHOTTKY RECTIFIER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
12CEX57E1A 制造商:GE 功能描述:RELAY
12CGQ150 制造商:International Rectifier 功能描述:Diode Schottky 150V 35A 3-Pin(3+Tab) TO-254AA 制造商:International Rectifier 功能描述:SCHOTTKY 150V 35A 3PIN TO-254AA - Bulk 制造商:International Rectifier 功能描述:SCHOTTKY RECTIFIER CMN CTHD 35A TO-254AA; Diode Type:Schottky; Diode Configuration:Dual Common Cathode; Repetitive Reverse Voltage Vrrm Max:150V; Forward Current If(AV):35A; Forward Voltage VF Max:1.6V; No. of Pins:3 ;RoHS Compliant: No
12CGQ150SCS 制造商:International Rectifier 功能描述:Diode Schottky 150V 35A 3-Pin(3+Tab) TO-254AA 制造商:International Rectifier 功能描述:SCHOTTKY 150V 35A 3PIN TO-254AA - Bulk
12CGQ150SCV 制造商:International Rectifier 功能描述:Diode Schottky 150V 35A 3-Pin(3+Tab) TO-254AA 制造商:Unity Microelectronics Inc 功能描述:SCHOTTKY DIODE, HI-REL, QIRL 制造商:International Rectifier 功能描述:SCHOTTKY 150V 35A 3PIN TO-254AA - Bulk
12CGQ150SCX 制造商:International Rectifier 功能描述:SCHOTTKY 150V 35A 3PIN TO-254AA - Bulk