NHI-15191RT データシートの表示（PDF） - Unspecified
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コンポーネント説明
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NHI-15191RT Datasheet PDF : 54 Pages
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T/ R
0= Indicates a receive message.
1= Indicates a transmit message.
Bits: 13
SADR / MODE
Bits: (12-8)
This field defines the sub- address or mode code.
Note: the interrupt level distinguishes between regular transmit/ receive commands and mode
commands.
4.2.8
REAL- TIME CLOCK
RTC HIGH WORD
Address: 5
R
RTC LOW WORD
Address: 6
R
The RTC is a 32 bit up- counter which can be used for time- tagging. If the time- tagging option
is in effect, the RTC is sampled and stored in 2 words in the data table The most significant
word is stored first.
When messages are time- tagged, the host should not write data to the first 2 locations
following the data table tag word since they will be overwritten with the value of the message time
tag.
The RTC can be reset by the mode command "Synchronize Without Data" and the least
significant 16 bits can be updated by "Synchronize With Data". The full 32 bits can be updated
using the first two data words in a receive command. See RTC CONTROL REGISTER for
details.
The RTC can be read and reset by the host at any time. Since the RTC consists of 32 bits, at
least 2 memory cycles are required to read all of its value. As a result, a carry- out from the lower
word can occur between the read cycles. A mechanism is therefore provided to solve this
potential difficulty.
If the host reads the RTC as two 16 bit words, *LOCK should be initialized to 1 in the RTC
CONTROL register. In this case, when the host reads the upper word, all 32 bits are latched into
the host output register. The value in the output register remains unchanged until the host
finishes reading the lower word of the RTC.
If the host reads the RTC in bytes, *LOCK should be initialized to 0. In this case, when the host
reads any of the bytes of the RTC, all 32 bits are latched into the host output register and its
value remains unchanged until updating is re- enabled by reading the RTC CONTROL register.
The RTC resolution can be programmed equal to 1, 2, 4, 8, 16, 32, or 64 microseconds.
4.2.9
RTC CONTROL REGISTER
Address: 7
R/ W
The RTC CONTROL register controls the RTC as well as having other functions.
15
RTC
RESET
7
M1760
14
RESET
LAST
6
BUSY
OPT
13
RES2
12
SYNUPD
11
*LOCK
10
SYNRST
9
RES1
8
RES0
5
RESET
BUSY
4
PRESET
4
3
PRESET
3
2
PRESET
2
1
PRESET
1
0
PRESET
0
RTC RESET
Bits: 15
When a "1" is written to RTC RESET, a reset pulse is issued to the RTC. The contents of the
register are not affected by this operation and RTC RESET is always read by the host as "0".
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