Rainbow Electronics DS1616 User Manual

Page 22

DS1616

22 of 28

Communication Reset (Asynchronous Mode)

When transmitting the command, parameters, or data to the DS1616, it is possible that communication
might be interrupted. For example, the user might accidentally disconnect the cable linking the device to
the host computer. To insure that communication always starts at a known state when in the
asynchronous mode, the DS1616 will reset the communication if it senses a problem. This is
accomplished via two methods. First, if during the transmission of a byte of data to the DS1616, the stop
bit is not received, communication will be reset. The lack of a valid stop bit indicates that that particular
byte of data was not received correctly. Second, if more then 10-bit times expire between the reception of
1 byte of data and the reception of the next required byte, then communication will be reset.

Automatic resetting of communication is not required when communicating in the synchronous mode.
This is because of the function of the

RST

pin. Pulling

RST

low resets the serial communication of the

DS1616.

DS1616 COMMANDS

All communication with the DS1616 is accomplished by writing a command to the device followed by
parameter byte/s if required. Table 3 illustrates the commands supported by the DS1616.

The DS1616 commands are summarized below. Note that if an invalid command is issued, no action is
taken by the device.

DS1616 COMMANDS Table 3

COMMAND

FUNCTION

DESCRIPTION

22h

Write Byte

Write 1 byte to RTC, Control registers, and User NV RAM

33h

Read Page

44h

Specification Test

Poll status of temperature and/or ADC Data extremes

55h

Read Data

Instructs DS1616 to immediately measure the temperature (if
CS0 = 1) and/or perform an analog to digital conversion on the
ADC Channels Selected (if CS[1-3] = 1) and store the result in
the Current Temperature and/or Current ADC Channel [1-3]
register(s) when MIP = 0.

A5h

Clear Memory

This command clears the datalog, histogram, Temperature
Alarm, ADC Channel 1 Alarm, Current Samples, Start Time
Stamp, Start Delay, and Sample Rate registers when the Clear
Enable bit (CLR) in the Control 1 register is set to a 1.

1. Write Byte (22h)
Host Transmit:

DS1616 Response: None

Note that good programming practice insists that the Clear Memory command should be issued whenever
the DS1616 is programmed to begin a new datalogging mission.