TDC-GPX acam messelectronic gmbh, TDC-GPX Datasheet - Page 8

• Manufacturer Part Number: TDC-GPX
• Description: Precision Time Interval Measurement
• Manufacturer: acam messelectronic gmbh

OEN operations – Driving the bus permanently
Note: With OEN = Low the output buffers are driving allthe time, with OEN = High they are driving only during a
read strobe. While writing to the TDC-GPX OEN has to be High.
Fake Reads for speeding up data readout
The maximum data readout rate is limited by the empty flag set time as it is not allowed to read from an empty
FIFO. This can be overcome by a second fake read strobe which is delayed to the read strobe at the TDC-GPX.
1.3.2 16 Bit Mode
The TDC-GPX data bus can be switched from 28 Bit to 16 Bit. This is done writing a 0x0000010 to address 14.
After that all read / write commands have to be done in pairs. When reading the last data from an interface FIFO
the empty flag disappears already with the first read command. Nonetheless it is mandatory to read a second
time.
The first read/write command always refers to the LSW, the second one to the MSW. The highest 4 Bit of the
MSW are not relevant (write) or shall be ignored (read).
Note: See Bug-Report 01 at the end of the datasheet
acam-messelectronic gmbh - Am Hasenbiel 27 - D-76297 Stutensee-Blankenloch - Germany - www.acam.de
DATA
OEN
t
Spec
OE-F
t
t
O E - R
O E - F
RDN
Data
ADR
EF1
EF2
High-Z
Data
ADR
RDN
RD*
EF
min.
max.
LSW1
OEN Rise to Data Valid
8
OEN Fall to Data Valid
Description
MSW1
valid
Data takeover
8
t
OE-R
LSW2
9
max.
min.
MSW2
Min (ns)
Figure 4
1.5
High-Z
1
Figure 5
Figure 3
Max (ns)
TDC-GPX
8.5
9