SX Device Programming Specifications Rev 2.2 4 © 2000 Scenix Semiconductor, Inc. All rights reserved. www.scenix.com (including the XT, LP, or HS mode), an external RC oscillator, or an external clock signal for normal
device operation, then you need to use the control signals and timing shown in Figure 2.1 to enter the
programming mode. If you are using the internal RC oscillator for normal device operation, then you
need to use the control signals and timing shown in Figure 2.2 to enter the programming mode. Figure 2.1 ISP Mode Entry with External Clocking Figure 2.2 ISP Mode Entry with the Internal RC Oscillator OSC1/Vpp OSC2 drive OSC1 low drive OSC1 to Vpp level Internal RC clock toggle OSC1 9 times (min) drive OSC2 low release OSC2, OSC2 is open drain 128 kHz OSC1/Vpp OSC2 Internal RC clock drive OSC2 long enough release OSC2 Vpp = 12.5V 4 MHz - 32kHz Internal RC changed to
128 kHz