TDA5235 Datasheet, PDF (88/259 Pages) Infineon Technologies AG – Enhanced Sensitivity Double-Configuration Receiver with Digital Baseband Processing

TDA5235
Functional Description
The following handling mechanism for read-clear registers was chosen due to
implementation of the Burst Read command:
• the current Interrupt Status (ISx) register 8-bit content is latched into the SPI shift
register after the last address bit is clocked-in (point A in Figure 58)
• the IS register is then cleared after last IS register bit is clocked out of the SPI
interface (point B in Figure 58)
Consequence: any interrupt event occurring in the window-time between points A and B
is cleared at point B and not stored/shown in an later readout of ISx.
(However: NINT signal is toggling in any case, if occurring interrupt is not masked in IMx
register)
irq1 (masked?)
nint
A
B
8-bit @2MHz = 4us
irq2 (masked?)
ncs
SPI IF
SFR IS* IS(t-1)
inst
addr
read /readb data = IS(t+0)
read/capture IS*
SFR IS* read clear
content
@end of data frame
IS(t+0)
IS(t+1) 0x00
Figure 58 ISx Readout Set Clear Collision
NOTE:
SFR IS(j) status flag is cleared
before it can be read if an IRQ
occurs during SPI data frame
Please see also the IMPORTANT NOTE in the Burst Read section !
Data Sheet
88
V1.0, 2010-02-19