System Clock Disable Register
| USBCLK | Disable USB FS Clock |
| PCK0 | Programmable Clock 0 Output Disable |
| PCK1 | Programmable Clock 1 Output Disable |
| PCK2 | Programmable Clock 2 Output Disable |
| PCK3 | Programmable Clock 3 Output Disable |
| PCK4 | Programmable Clock 4 Output Disable |
| PCK5 | Programmable Clock 5 Output Disable |
| PCK6 | Programmable Clock 6 Output Disable |
| PCK7 | Programmable Clock 7 Output Disable |