LM629M-6: An 8-bit Output Motion-Control Processor

The LM629M-6, a component product under the Telecom ICs/chipsets on hqew.net, is among the electronic components series of LM629M. Similar with the LM628 series, the LM629M also has an 8-bit output which can drive either an 8-bit or a 12-bit DAC. In addition, LM629-based system provides an 8-bit PWM output for directly driving H-switches. The parts are fabricated in NMOS and packaged in a 28-pin dual in-line package or a 24-pin surface mount package. Both 6 MHz and 8 MHz maximum frequency versions are available with the suffixes -6 and -8, respectively, used to designate the versions. They incorporate an SDA core processor and cells designed by SDA.

Here are part descriptions of Pinout：

Pin numbers for the 24-pin surface mount package are indicated in parentheses. Pin 1 (17), Index (IN) Input: Receives optional index pulse from the encoder. Must be tied high if not used. The index position is read when Pins 1, 2, and 3 are low. Pins 2 and 3 (18 and 19), Encoder Signal (A, B) Inputs: Receive the two-phase quadrature signals provided by the incremental encoder.

When the motor is rotating in the positive (“forward”) direction, the signal at Pin 2 leads the signal at Pin 3 by 90 degrees. Note that the signals at Pins 2 and 3 must remain at each encoder state (See Figure 9) for a minimum of 8 clock periods in order to be recognized.

Because of a four-to-one resolution advantage gained by the method of decoding the quadrature encoder signals, this corresponds to a maximum encoder-state capture rate of 1.0 MHz (fCLK = 8.0 MHz) or 750 kHz (fCLK = 6.0 MHz). For other clock frequencies the encoder signals must also remain at each state a minimum of 8 clock periods.

Pins 4 to 11 (20 to 24 and 2 to 4), Host I/O Port (D0 to D7): Bi-directional data port which connects to host computer/ processor. Used for writing commands and data to the LM628, and for reading the status byte and data from the LM628, as controlled by CS (Pin 12), PS (Pin 16), RD (Pin13), and WR (Pin 15).Pin 12 (5), Chip Select (CS ) Input: Used to select the LM628 for writing and reading operations. Pin 13 (6), Read (RD ) Input: Used to read status and data. Pin 14 (7), Ground (GND): Power-supply return pin. Pin 15 (8), Write (WR ) Input: Used to write commands and data. Pin 16 (9), Port Select (PS ) Input: Used to select command or data port. Selects command port when low, data port when high.