Rockwell SoniCrafter BT8960 - Manual (Page 42)

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2.0 Functional Description
2.5 Microcomputer Interface
Bt8960
Single-Chip 2B1Q Transceiver
N8960DSB
2.5 Microcomputer Interface
The microcomputer interface provides operational mode control and status
through internal registers. A microcomputer write sets the operating modes to the
appropriate registers. A read to a register verifies the operating mode or provides
the status. The microcomputer interface can be programmed to generate an inter-
rupt on certain conditions.
2.5.1 Source Code
Rockwell provides portable C-source code under a no-cost licensing agreement.
This source code provides a startup procedure, as well as diagnostic and system
monitoring functions.
2.5.2 Microcomputer Read/Write
The microcomputer interface uses either an 8-bit-wide multiplexed address-data
bus (Intel-style), or an 8-bit-wide data bus and another separate 8-bit-wide
address bus (Motorola-style) for external data communications. The interface
provides access to the internal control and status registers, coefficients, and
microcode RAM. The interface is compatible with Intel or Motorola microcom-
puters, and is configured with the inputs, MOTEL and MUXED. MOTEL low
selects Intel-type microcomputer and control signals: ALE, CS, RD, and WR.
MOTEL high selects Motorola-type microcomputer and control signals: ALE,
CS, DS, and R/W. MUXED high configures the interface to use the multiplexed
address-data bus with both the address and data on the AD[7:0] pins. MUXED
low configures the interface to use separate address and data bused with the data
on the AD[7:0] pins and the address on the ADDR[7:0] pins. The READY pin is
provided to indicate when the Bt8960 is ready to transfer data and can be used by
the microcomputer to insert wait states in read or write cycle.
The microcomputer interface provides access to a 256-byte internal address
space. These registers provide configuration, control, status, and monitoring capa-
bilities. Meter values are read lower-byte then upper-byte. When the lower-byte is
read, the upper-byte is latched at the corresponding value. This ensures that multi-
ple byte values correspond to the same reading. Most information can be directly
read or written; however, the filter coefficients require an indirect access.