PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 74

• Manufacturer Part Number: PSB7238
• Description: Joint Audio Decoder-Encoder - Multimode
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

PSB 7238
Functional Blocks
Upon the reception of the next byte the hardware sets the MDR status bit. When the
monitor byte is read from the MONR register, this byte is acknowledged via transmit
MR = 0. Every new byte is similarly indicated by the MDR status, and acknowledged
after a read of the MONR register. If the hardware recognizes the end of a packet, it
indicates this via the MER status (MRE = 1).
The receiver of the PSB 7238 does not perform a double-last-look check on the received
data (i.e. compare the data received while MX = 0 with the data in the previous frame
with MX = 1).
When MRC = 0, it is made sure that the receiver only receives the first byte of a packet
and does not latch any further bytes in MONR until the beginning of the next packet.
Thus the conditions for latching the first byte of a packet is:
(MRE = 1) & (MX = 0 after having been 1 in at least two consecutive frames).
Any further bytes are latched into MONR only if:
(MRE MRC = 1) & (previously received byte has been read from MONR register) &
(MX = 0).
Figure 33
Semiconductor Group
74
Data Sheet 1998-07-01