PEB20534H-10 SIEMENS [Siemens Semiconductor Group], PEB20534H-10 Datasheet - Page 109

• Manufacturer Part Number: PEB20534H-10
• Description: DMA Supported Serial Communication Controller with 4 Channels DSCC4
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

regain-sequence. Even if LBREQ is activated earlier the regain-sequence is initiated by
LHOLD going high. LBREQ and LHOLD are connected via an external arbitration
circuitry. Please note that LHOLD may also be deactivated without the EBC requesting
the bus.
Figure 31 below shows the correct connection of the bus arbitration signals between the
master and the slave. In order to provide correct levels during initialization of the master
and the slave, two external pull-up devices are required. One is connected to the
master’s LHOLD input, the other to the slave’s LHLDA input.
Figure 30
The falling LBREQ edge shows the last chance for LBREQ to trigger the indicated
Note: For compatibility reasons with existing applications, these pull-ups can not be
Semiconductor Group
LHOLD
(input)
LHLDA
(output)
LBREQ
(output)
LCSO
(output)
LRD, LWR
(output signals)
integrated into the chip.
External Bus Arbitration (Regaining the Bus)
109
Multi Function Port (MFP)
Data Sheet 09.98
PEB 20534
ITD10616