Hitachi C4K60 Specifications - Page 74

7.5.13. Initialize Device Parameters [91h] Task File Registers Command LBA High LBA Mid LBA Low Device/Head Sector Count Features 7 6 5 4 3 2 1 0 91h XX XX XX X 0 X DRV number of heads minus 1 per cylinder Number of sectors per track XX These parameters allow the host to set the number of sectors per track and the number of heads per cylinder. Upon receipt of the command, the device sets BSY, saves the specified parameters, clears BSY, and generates an interrupt. The only two register values that this command uses are the Sector Count Register that specifies the number of sectors per track, and the Device/Head Register that specifies the number of heads minus 1. The sector count and head values are not checked for validity by this command. If they are invalid, no error will be posted until an illegal access is made by some other command. 7.5.14. Read Buffer [E4h] Task File Registers Command LBA High LBA Mid LBA Low Device/Head Sector Count Features 7 6 5 4 3 2 1 0 E4h XX XX XX X X X DRV X X X X XX XX The READ BUFFER command enables the host to read the current contents of the device's sector buffer. When this command is issued, the device sets BSY, sets up the sector buffer for a read operation, sets DRQ, clears BSY, and generates an interrupt. The host then reads up to 512 bytes of data from the sector buffer. K6610170 Rev.2 Dec 22, 2004 - 74 -