Материал: DS1621

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DS1621

measurement will be completed and the DS1621 will remain idle until a Start Convert T is issued to resume continuous operation.

DS1621 COMMAND SET Table 3

			2-WIRE BUS DATA
			AFTER ISSUING
INSTRUCTION	DESCRIPTION	PROTOCOL	PROTOCOL	NOTES

TEMPERATURE CONVERSION COMMANDS

Read Temperature Read last converted temperature AAh <read 2 bytes data> value from temperature register.

Read Counter	Reads value of count remaining	A8h	<read data>
	from counter.
Read Slope	Reads value of the slope	A9h	<read data>
	accumulator.
Start Convert T	Initiates temperature	EEh	idle	1
	conversion.
Stop Convert T	Halts temperature conversion.	22h	idle	1
	THERMOSTAT COMMANDS
Access TH	Reads or writes high	A1h	<write data>	2
	temperature limit value into TH
	register.
Access TL	Reads or writes low	A2h	<write data>	2
	temperature limit value into TL
	register.
Access Config	Reads or writes configuration	ACh	<write data>	2
	data to configuration register.

NOTES:

1.In continuous conversion mode a Stop Convert T command will halt continuous conversion. To restart the Start Convert T command must be issued. In one–shot mode a Start Convert T command must be issued for every temperature reading desired.

2.Writing to the E2 typically requires 10ms at room temperature. After issuing a write command, no further writes should be requested for at least 10 ms.

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MEMORY FUNCTION EXAMPLE

Example: Bus master sets up DS1621 for continuous conversion and thermostatic function.

BUS MASTER	DS1621	DATA (MSB
MODE	MODE	FIRST)	COMMENTS
TX	RX	START	Bus Master initiates a START condition.
TX	RX	<address,0>	Bus Master sends DS1621 address; R/		= 0.
				W
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	ACh	Bus Master sends Access Config command protocol.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	02h	Bus Master sets up DS1621 for output polarity active
			high, continuous conversion.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	START	Bus Master generates a repeated START condition.
TX	RX	<address,0>	Bus Master sends DS1621 address; R/		= 0.
				W
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	A1h	Bus Master sends Access TH command.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	28h	Bus Master sends first byte of data for TH limit of
			+40°C.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	00h	Bus Master sends second byte of data for TH limit of
			+40°C.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	START	Bus Master generates a repeated START condition.
TX	RX	<address,0>	Bus Master sends DS1621 address; R/		= 0.
				W
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	A2h	Bus Master sends Access TL command.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	0Ah	Bus Master sends first byte of data for TL limit of
			+10°C.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	00h	Bus Master sends second byte of data for TL limit of
			+10°C.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	START	Bus Master generates a repeated START condition.
TX	RX	<address,0>	Bus Master sends DS1621 address; R/		= 0.
				W
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	EEh	Bus Master sends Start Convert T command protocol.
RX	TX	ACK	DS1621 generates acknowledge bit.
TX	RX	STOP	Bus Master initiates STOP condition.

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DS1621

ABSOLUTE MAXIMUM RATINGS*

Voltage on Any Pin Relative to Ground	–0.5V to +7.0V
Operating Temperature	–55°C to +125°C
Storage Temperature	–55°C to +125°C
Soldering Temperature	260°C for 10 seconds

*This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

RECOMMENDED DC OPERATING CONDITIONS

PARAMETER	SYMBOL	MIN	TYP	MAX	UNITS	NOTES
Supply Voltage	VDD	2.7		5.5	V	1

DC ELECTRICAL CHARACTERISTICS			(-55°C to +125°C; VDD=2.7V to 5.5V)
PARAMETER	SYMBOL	CONDITION	MIN	TYP	MAX	UNITS	NOTES
Thermometer Error	TERR	0°C to 70°C			±½	°C
		-55°C to + 0°C					11
		and		See Typical Curve
		70°C to 125°C
Low Level Input	VIL		0.5		0.3 VDD	V
Voltage
High Level Input	VIH		0.7 VDD		VDD+0.5	V
Voltage
Pulse width of
spikes which must	tSP	Fast Mode	0		50	ns
be suppressed by
the input filter
Low Level Output	VOL1	3 mA Sink	0		0.4	V
Voltage		Current
	VOL2	6 mA Sink	0		0.6	V
		Current
Input Current each		0.4<VI/O<0.9VDD	-10		10	µA	2
I/O Pin
I/O Capacitance	CI/O				10	pF
		Temperature
		Conversion			1000
Active Supply	ICC	E2 Write			400	µA	3, 4
Current		Communi-			100
		cation Only
Standby Supply	ISTBY				1	µA	3, 4
Current
Thermostat Output	VOH	1 mA Source	2.4			V
(TOUT) Output	VOL	4 mA Sink			0.4	V
Voltage

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							DS1621
AC ELECTRICAL CHARACTERISTICS			(-55°C to +125°C; VDD=2.7V to 5.5V)
PARAMETER	SYMBOL	CONDITION	MIN	TYP	MAX	UNITS	NOTES
Temperature	TTC			0.4	1	s
Conversion Time
NV Write Cycle	tWR	0°C to 70°C		10	50	ms	10
Time
SCL Clock	fSCL	Fast Mode	0		400	KHz
Frequency		Standard Mode	0		100
Bus Free Time	tBUF	Fast Mode	1.3			µs
Between a STOP		Standard Mode	4.7
and START
Condition
Hold Time	tHD:STA	Fast Mode	0.6			µs	5
(Repeated) START		Standard Mode	4.0
Condition
Low Period of SCL	TLOW	Fast Mode	1.3			µs
Clock		Standard Mode	4.7
High Period of SCL	THIGH	Fast Mode	0.6			µs
Clock		Standard Mode	4.0
Setup Time for a	tSU:STA	Fast Mode	0.6			µs
Repeated START		Standard Mode	4.7
Condition
Data Hold Time	tHD:DAT	Fast Mode	0		0.9	µs	6, 7
		Standard Mode	0
Data Setup Time	tSU:DAT	Fast Mode	100			ns	8
		Standard Mode	250
Rise Time of Both	tR	Fast Mode	20+0.1CB		300	ns	9
SDA and SCL		Standard Mode			1000
Signals
Fall Time of both	tF	Fast Mode	20+0.1CB		300	ns	9
SDA and SCL		Standard Mode			300
Signals
Setup time for	tSU:STO	Fast Mode	0.6			µs
STOP Condition		Standard Mode	4.0
Capacitative Load	Cb				400	pF
for each Bus Line

All values referred to VIH=0.9 VDD and VIL=0.1 VDD.

AC ELECTRICAL CHARACTERISTICS			(-55°C to +125°C; VDD=2.7V to 5.5V)
PARAMETER	SYMBOL	MIN	TYP	MAX	UNITS	NOTES
Input Capacitance	CI		5		pF

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NOTES:

1.All voltages are referenced to ground.

2.I/O pins of fast mode devices must not obstruct the SDA and SCL lines if VDD is switched off.

3.ICC specified with TOUT pin open.

4.ICC specified with VCC at 5.0V and SDA, SCL = 5.0V, 0°C to 70°C.

5.After this period, the first clock pulse is generated.

6.A device must internally provide a hold time of at least 300 ns for the SDA signal (referred to the VIH MIN of the SCL signal) in order to bridge the undefined region of the falling edge of SCL.

7.The maximum tHD:DAT has only to be met if the device does not stretch the LOW period (tLOW) of the SCL signal.

8.A fast mode device can be used in a standard mode system, but the requirement tSU:DAT >250 ns must then be met. This will automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line tRMAX+tSU:DAT = 1000+250 = 1250 ns before the SCL line is released.

9.Cb – total capacitance of one bus line in pF.

10.Writing to the nonvolatile memory should only take place in the 0°C to 70°C temperature range.

11.See typical curve for specification limits outside 0°C to 70°C range. Thermometer error reflects sensor accuracy as tested during calibration.

TIMING DIAGRAM

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