Media Local Bus (MLB)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
33-18
Freescale Semiconductor
Preliminary
33.4
Functional Description
The MLB topology supports communications between a single MLB controller (INIC) and one or several
MLB devices (for example, MPC551xE/G). The 3-pin interface consists of an MLBCLK clock (generated
by the MLB controller), an MLBSIG signal, and MLBDAT data lines. In this interface, MLBSIG and
MLBDAT are bidirectional. In the 5-pin interface, all signals are unidirectional (MLBSI, MLBSO,
MLBDI, MLBDO, and MLBCLK). The implementation on the MPC551xE/G also includes Level Shifter
Enable control signals (MLBSIG_BUFEN and MLBDAT_BUFEN) for the 3-pin interface, and setup and
debug signals (MLB_SIGOBS, MLB_DATOBS, and MLB_SLOT). See
Section 33.2, “External Signal
” description for a full details.
The MLB controller is the interface between the MLB devices and the MOST network.
shows the MLB topology with the MPC551xE/G as the MLB device and the INIC as the MLB controller.
The 5-pin interface is shown.
Table 33-13. MLB TX Isochronous Channel Address Register (MLB_TXICHAR) Field Descriptions
Field
Description
TXICHA_ACEN
TX Isochronous Channel Address Comparison Enable. When enabled a received Channel Address is
compared against the TX Isochronous Channel Address configured in this register. TXICHA_ACEN
should only be updated when MDIS is set.
0 TX Isochronous Channel Address comparison disabled (default out of reset)
1 TX Isochronous Channel Address comparison enabled
bits 1–25
Reserved.
TXICHA
TX Isochronous Channel Address. If TXICHA_ACEN=1, this address will be compared against the logical
address that was driven on the bus by the MLB controller (INIC). If the received channel address matches
the programmed value in the MLB_TXICHAR register the appropriate output buffer enables are driven
(
Section 33.4.2.1.4, “MLBSIG_BUFEN and MLBDAT_BUFEN
”).
Although Channel Addresses are defined to be sixteen bits wide, bits 15 through 9 and the LSB are
always zero. The odd addresses are reserved and Channel Address 0x0000 is the bus idle state. Only
the 31 even addresses between 0x0002 and 0x003E are allowed; therefore, only five bits per Channel
Address are required to be configured. TXICHA should only be updated when MDIS is set.
An address match occurs when TXICHA_ACEN is set and the received 16-bit Channel Address equals
16b0000_0000_00_{RXICHA}_0.
bit 31
Reserved.