July 30, 1998 ET 4 atari

### NAME

et - driver for ET4000 VME graphics cards

### SYNOPSIS

et0 at vme0

### DESCRIPTION

The et device driver supports VME graphics cards based on the Tseng ET4000 chipset. It supports the minimal ioctl's needed to run X11. The 8Kb control registers are mapped from offset 0x0 to offset 0x1fff and the 1MB frame buffer is mapped from offset 0x400000 to offset 0x4fffff. VGA compatible memory is mapped from offset 0xa0000 to offset 0xc0000.

### HARDWARE

Cards supported by the et driver include:

  Crazy Dots II VME graphics card

### NOTES

The clock generator on the Crazy Dots card is an ICS 1394M. Setting the clock is done by writing to a register at offset 0x0. This address cannot be read. The values that can be written to the register and the associated clock are:

Value | Clock
```0x00` | 14318
```0x10` | 16257
```0x17` | 20000
```0x0c` | 24000
```0x04` | 25175
```0x14` | 28332
```0x18` | 32514
```0x1a` | 36000
```0x1c` | 40000
```0x03` | 44900
```0x0f` | 50000
```0x13` | 50344
```0x07` | 56644
```0x11` | 65028
```0x1f` | 80000

### FILES

```/dev/etvme`

### AUTHORS

Julian Coleman

### BUGS

The driver does not support a text mode, so cannot be used as a console.